Error when comparing equality of indexes
In 0.16.0 comparing MultiIndices using `==` raises an exception.

``` python
from StringIO import StringIO
import pandas as pd

# create a series using a multiindex
df = pd.read_csv(StringIO('a,b,c\n1,2,3'), index_col=[0, 1])
series = df['c']

series.index == series.index
#   File "/Users/dan/venvs/pandas-0.16.0/lib/python2.7/site-packages/pandas/core/index.py", line 54, in wrapper
#     func = getattr(self._data.view(np.ndarray), opname)
# AttributeError: 'NoneType' object has no attribute 'view'

print pd.__version__
#0.16.0
```

Another one I've come across is that there is an `AttributeError` when comparing indexes for which the underlying numpy arrays cannot be broadcast together. The error message itself is very obscure. I gather that `.equals()` can be used for what I'm trying to do in these examples, but still the errors when using `==` are surprising.

```
>>> pd.Index(['a', 'b']) == pd.Index(['a', 'b', 'c'])
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-2-44325051df92> in <module>()
----> 1 pd.Index(['a', 'b']) == pd.Index(['a', 'b', 'c'])

/Users/dan/venvs/pandas-0.16.0/lib/python2.7/site-packages/pandas/core/index.pyc in wrapper(self, other)
     57         # technically we could support bool dtyped Index
     58         # for now just return the indexing array directly
---> 59         if is_bool_dtype(result):
     60             return result
     61         try:

/Users/dan/venvs/pandas-0.16.0/lib/python2.7/site-packages/pandas/core/common.py in is_bool_dtype(arr_or_dtype)
   2510
   2511 def is_bool_dtype(arr_or_dtype):
-> 2512     tipo = _get_dtype_type(arr_or_dtype)
   2513     return issubclass(tipo, np.bool_)
   2514

/Users/dan/venvs/pandas-0.16.0/lib/python2.7/site-packages/pandas/core/common.py in _get_dtype_type(arr_or_dtype)
   2439     elif isinstance(arr_or_dtype, CategoricalDtype):
   2440         return CategoricalDtypeType
-> 2441     return arr_or_dtype.dtype.type
   2442
   2443

AttributeError: 'NotImplementedType' object has no attribute 'dtype'
```
