ValueError adding boolean dataframe to panel fails in 0.16.2 but not 0.15.2
In Pandas 0.16.2 an attempt to assign a boolean array (created by pd.notnull) to a Panel fails with "ValueError: could not broadcast input array from shape...".  The same code is successful using Pandas 0.15.2.

``` python
>>> import pandas as pd
>>> import numpy as np
>>> 
>>> # create a test panel
... dates = pd.date_range('20150101', periods=6)
>>> df1 = pd.DataFrame([0,-.1,.2,np.nan,.23,np.nan], index=dates, columns=list('A'))
>>> df2 = pd.DataFrame([.3,np.nan,.3,np.nan,.6,.1], index=dates, columns=list('A'))
>>> data = {'Item1' : df1, 'Item2': df2}
>>> panel = pd.Panel(data)
>>> 
>>> # check the shape
... panel.loc[:, :, 'A'].shape
(6, 2)
>>> 
>>> # create a dataframe with boolean values indicating not null data values
... notnull = pd.notnull(panel.loc[:, :, 'A'])
>>> notnull.shape
(6, 2)
>>> 
>>> # attempt to store it in the panel
... panel.loc[:, :, 'NotNull'] = notnull
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/indexing.py", line 115, in __setitem__
    self._setitem_with_indexer(indexer, value)
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/indexing.py", line 445, in _setitem_with_indexer
    setter(item, v)
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/indexing.py", line 411, in setter
    s._data = s._data.setitem(indexer=pi, value=v)
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/internals.py", line 2483, in setitem
    return self.apply('setitem', **kwargs)
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/internals.py", line 2459, in apply
    applied = getattr(b, f)(**kwargs)
  File "/Users/edb/anaconda2/lib/python2.7/site-packages/pandas/core/internals.py", line 611, in setitem
    values[indexer] = value
ValueError: could not broadcast input array from shape (2) into shape (6)
>>> 
```

pd.show_versions() output for the failing version:

``` python
>>> pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.10.final.0
python-bits: 64
OS: Darwin
OS-release: 14.5.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.16.2
nose: 1.3.7
Cython: 0.22.1
numpy: 1.9.2
scipy: 0.15.1
statsmodels: 0.6.1
IPython: 3.2.0
sphinx: 1.3.1
patsy: 0.3.0
dateutil: 2.4.2
pytz: 2015.4
bottleneck: 1.0.0
tables: 3.2.0
numexpr: 2.4.3
matplotlib: 1.4.3
openpyxl: 1.8.5
xlrd: 0.9.3
xlwt: 1.0.0
xlsxwriter: 0.7.3
lxml: 3.4.4
bs4: 4.3.2
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.5
pymysql: None
psycopg2: None
>>>
```

pd.show_versions() for the working version:

``` python
pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.9.final.0
python-bits: 64
OS: Darwin
OS-release: 14.5.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.15.2
nose: 1.3.4
Cython: 0.22
numpy: 1.9.2
scipy: 0.15.1
statsmodels: 0.6.1
IPython: 3.0.0
sphinx: 1.2.3
patsy: 0.3.0
dateutil: 2.4.1
pytz: 2015.2
bottleneck: None
tables: 3.1.1
numexpr: 2.3.1
matplotlib: 1.4.3
openpyxl: 1.8.5
xlrd: 0.9.3
xlwt: 0.7.5
xlsxwriter: 0.6.7
lxml: 3.4.2
bs4: 4.3.2
html5lib: None
httplib2: None
apiclient: None
rpy2: None
sqlalchemy: 0.9.9
pymysql: None
psycopg2: None
>>> 
```
