Clean Up Sphinx Warnings
A fresh build of the docs locally yields all of the below warnings:

<details> 

```sh
as-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
WARNING: [autosummary] failed to import 'pandas.SparseArray.get_values': no module named pandas.SparseArray.get_values
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
/Users/williamayd/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/sphinx/ext/autosummary/__init__.py:635: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
  obj = getattr(obj, obj_name)
WARNING: [autosummary] failed to import 'pandas.SparseArray.values': no module named pandas.SparseArray.values
WARNING: [autosummary] failed to import 'pandas.Timestamp.weekday_name': no module named pandas.Timestamp.weekday_name
WARNING: [autosummary] failed to import 'pandas.Timestamp.weekday_name': no module named pandas.Timestamp.weekday_name
WARNING: [autosummary] failed to import 'pandas.arrays.DatetimeArray.timetuple': no module named pandas.arrays.DatetimeArray.timetuple
WARNING: [autosummary] failed to import 'pandas.arrays.DatetimeArray.weekday_name': no module named pandas.arrays.DatetimeArray.weekday_name
WARNING: [autosummary] failed to import 'pandas.core.series.Series.as_blocks': no module named pandas.core.series.Series.as_blocks
WARNING: [autosummary] failed to import 'pandas.core.series.Series.as_matrix': no module named pandas.core.series.Series.as_matrix
WARNING: [autosummary] failed to import 'pandas.core.series.Series.asobject': no module named pandas.core.series.Series.asobject
WARNING: [autosummary] failed to import 'pandas.core.series.Series.base': no module named pandas.core.series.Series.base
WARNING: [autosummary] failed to import 'pandas.core.series.Series.blocks': no module named pandas.core.series.Series.blocks
WARNING: [autosummary] failed to import 'pandas.core.series.Series.clip_lower': no module named pandas.core.series.Series.clip_lower
WARNING: [autosummary] failed to import 'pandas.core.series.Series.clip_upper': no module named pandas.core.series.Series.clip_upper
WARNING: [autosummary] failed to import 'pandas.core.series.Series.compound': no module named pandas.core.series.Series.compound
WARNING: [autosummary] failed to import 'pandas.core.series.Series.compress': no module named pandas.core.series.Series.compress
WARNING: [autosummary] failed to import 'pandas.core.series.Series.convert_objects': no module named pandas.core.series.Series.convert_objects
WARNING: [autosummary] failed to import 'pandas.core.series.Series.data': no module named pandas.core.series.Series.data
WARNING: [autosummary] failed to import 'pandas.core.series.Series.flags': no module named pandas.core.series.Series.flags
WARNING: [autosummary] failed to import 'pandas.core.series.Series.from_array': no module named pandas.core.series.Series.from_array
WARNING: [autosummary] failed to import 'pandas.core.series.Series.from_csv': no module named pandas.core.series.Series.from_csv
WARNING: [autosummary] failed to import 'pandas.core.series.Series.ftype': no module named pandas.core.series.Series.ftype
WARNING: [autosummary] failed to import 'pandas.core.series.Series.ftypes': no module named pandas.core.series.Series.ftypes
WARNING: [autosummary] failed to import 'pandas.core.series.Series.get_dtype_counts': no module named pandas.core.series.Series.get_dtype_counts
WARNING: [autosummary] failed to import 'pandas.core.series.Series.get_ftype_counts': no module named pandas.core.series.Series.get_ftype_counts
WARNING: [autosummary] failed to import 'pandas.core.series.Series.get_value': no module named pandas.core.series.Series.get_value
WARNING: [autosummary] failed to import 'pandas.core.series.Series.get_values': no module named pandas.core.series.Series.get_values
WARNING: [autosummary] failed to import 'pandas.core.series.Series.imag': no module named pandas.core.series.Series.imag
WARNING: [autosummary] failed to import 'pandas.core.series.Series.is_copy': no module named pandas.core.series.Series.is_copy
WARNING: [autosummary] failed to import 'pandas.core.series.Series.itemsize': no module named pandas.core.series.Series.itemsize
WARNING: [autosummary] failed to import 'pandas.core.series.Series.ix': no module named pandas.core.series.Series.ix
WARNING: [autosummary] failed to import 'pandas.core.series.Series.nonzero': no module named pandas.core.series.Series.nonzero
WARNING: [autosummary] failed to import 'pandas.core.series.Series.ptp': no module named pandas.core.series.Series.ptp
WARNING: [autosummary] failed to import 'pandas.core.series.Series.put': no module named pandas.core.series.Series.put
WARNING: [autosummary] failed to import 'pandas.core.series.Series.real': no module named pandas.core.series.Series.real
WARNING: [autosummary] failed to import 'pandas.core.series.Series.reindex_axis': no module named pandas.core.series.Series.reindex_axis
WARNING: [autosummary] failed to import 'pandas.core.series.Series.select': no module named pandas.core.series.Series.select
WARNING: [autosummary] failed to import 'pandas.core.series.Series.set_value': no module named pandas.core.series.Series.set_value
WARNING: [autosummary] failed to import 'pandas.core.series.Series.strides': no module named pandas.core.series.Series.strides
WARNING: [autosummary] failed to import 'pandas.core.series.Series.timetuple': no module named pandas.core.series.Series.timetuple
WARNING: [autosummary] failed to import 'pandas.core.series.Series.to_dense': no module named pandas.core.series.Series.to_dense
WARNING: [autosummary] failed to import 'pandas.core.series.Series.to_msgpack': no module named pandas.core.series.Series.to_msgpack
WARNING: [autosummary] failed to import 'pandas.core.series.Series.to_sparse': no module named pandas.core.series.Series.to_sparse
WARNING: [autosummary] failed to import 'pandas.core.series.Series.valid': no module named pandas.core.series.Series.valid
```

</details>

I believe these are just removed features and we should probably just remove from the docs as well