style apply of rows fails for subset list, but works for single row?
#### Code Sample, a copy-pastable example if possible

```
df = pd.DataFrame([["A", 1],["B", 2]], columns=["Letter", "Number"])
def highlight(s):
    return ['background-color: yellow']
df.style.apply(highlight, axis=0, subset=[0])

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/Users/paulperry/anaconda/lib/python3.5/site-packages/IPython/core/formatters.py in __call__(self, obj)
    341             method = _safe_get_formatter_method(obj, self.print_method)
    342             if method is not None:
--> 343                 return method()
    344             return None
    345         else:

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/style.py in _repr_html_(self)
    163     def _repr_html_(self):
    164         """Hooks into Jupyter notebook rich display system."""
--> 165         return self.render()
    166 
    167     def _translate(self):

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/style.py in render(self)
    356         the rendered HTML in the notebook.
    357         """
--> 358         self._compute()
    359         d = self._translate()
    360         # filter out empty styles, every cell will have a class

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/style.py in _compute(self)
    422         r = self
    423         for func, args, kwargs in self._todo:
--> 424             r = func(self)(*args, **kwargs)
    425         return r
    426 

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/style.py in _apply(self, func, axis, subset, **kwargs)
    429         subset = _non_reducing_slice(subset)
    430         if axis is not None:
--> 431             result = self.data.loc[subset].apply(func, axis=axis, **kwargs)
    432         else:
    433             # like tee

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/indexing.py in __getitem__(self, key)
   1282     def __getitem__(self, key):
   1283         if type(key) is tuple:
-> 1284             return self._getitem_tuple(key)
   1285         else:
   1286             return self._getitem_axis(key, axis=0)

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/indexing.py in _getitem_tuple(self, tup)
    783 
    784         # no multi-index, so validate all of the indexers
--> 785         self._has_valid_tuple(tup)
    786 
    787         # ugly hack for GH #836

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/indexing.py in _has_valid_tuple(self, key)
    136             if i >= self.obj.ndim:
    137                 raise IndexingError('Too many indexers')
--> 138             if not self._has_valid_type(k, i):
    139                 raise ValueError("Location based indexing can only have [%s] "
    140                                  "types" % self._valid_types)

/Users/paulperry/anaconda/lib/python3.5/site-packages/pandas/core/indexing.py in _has_valid_type(self, key, axis)
   1365 
   1366                 raise KeyError("None of [%s] are in the [%s]" %
-> 1367                                (key, self.obj._get_axis_name(axis)))
   1368 
   1369             return True

KeyError: 'None of [[0]] are in the [columns]'

Out[16]:
<pandas.core.style.Styler at 0x11ae32cf8>
```

The code appears to be applying it to the columns, not the rows, but passing a single value as the subset renders the table with the correct row highlighted.  

```
df.style.apply(highlight, axis=0, subset=0)

Letter  Number
0   A   1    <- in html this row is highlighted yellow
1   B   2
```

Passing a bad row index (e.g. 3) also correctly fails with 'None of [[3]] are in the [index]'

`df.style.apply(highlight, axis=1, subset=['Letter'])` works, but
`df.style.apply(highlight, axis=1, subset=['Letter','Number'])` Fails
#### Expected Output

```
df.style.apply(highlight, axis=0, subset=[0])

Letter  Number
0   A   1    <- in html this row should be highlighted yellow
1   B   2

```
#### output of `pd.show_versions()`
## INSTALLED VERSIONS

commit: None
python: 3.5.1.final.0
python-bits: 64
OS: Darwin
OS-release: 15.4.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.18.0
nose: 1.3.7
pip: 8.1.2
setuptools: 20.3
Cython: 0.23.4
numpy: 1.10.4
scipy: 0.17.0
statsmodels: 0.6.1
xarray: None
IPython: 4.1.2
sphinx: 1.3.5
patsy: 0.4.0
dateutil: 2.5.1
pytz: 2016.2
blosc: None
bottleneck: 1.0.0
tables: 3.2.2
numexpr: 2.5
matplotlib: 1.5.1
openpyxl: 2.3.2
xlrd: 0.9.4
xlwt: 1.0.0
xlsxwriter: 0.8.4
lxml: 3.6.0
bs4: 4.4.1
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.12
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.39.0
