Panel resample by periods does not work in 0.17.1 for certain panels
This code works in 0.15.2 but breaks in 0.17.1

``` python
import pandas as pd
import numpy as np

pd.show_versions()

items = ['foo']
major_axis = pd.date_range('2013-04-01', '2013-06-30')
minor_axis = [0]

p = pd.Panel(
    np.ones(major_axis.size).reshape(1, -1, 1),
    items=items,
    major_axis=major_axis
)

p.resample('Q', how='mean', axis=1, kind='period')
```
### 0.15.2:

```
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 26 Stepping 5, GenuineIntel
byteorder: little
LC_ALL: None
LANG: en_GB

pandas: 0.15.2
nose: 1.3.7
Cython: 0.22
numpy: 1.9.3
scipy: 0.16.0
statsmodels: None
IPython: 3.2.1
sphinx: 1.3.1
patsy: 0.3.0
dateutil: 2.4.1
pytz: 2015.7
bottleneck: 1.0.0
tables: 3.2.0
numexpr: 2.4.3
matplotlib: 1.4.3
openpyxl: 1.8.5
xlrd: 0.9.4
xlwt: 0.7.5
xlsxwriter: 0.7.3
lxml: 3.4.4
bs4: 4.3.2
html5lib: 0.999
httplib2: None
apiclient: None
rpy2: None
sqlalchemy: 1.0.9
pymysql: None
psycopg2: None
Out[1]: 
<class 'pandas.core.panel.Panel'>
Dimensions: 1 (items) x 1 (major_axis) x 1 (minor_axis)
Items axis: foo to foo
Major_axis axis: 2013Q2 to 2013Q2
Minor_axis axis: 0 to 0
```
### 0.17.1:

```
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.11.final.0
python-bits: 64
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 26 Stepping 5, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None

pandas: 0.17.1
nose: 1.3.7
pip: 7.1.2
setuptools: 19.1.1
Cython: 0.23.4
numpy: 1.10.2
scipy: 0.16.0
statsmodels: 0.6.1
IPython: 3.2.1
sphinx: 1.3
patsy: 0.4.0
dateutil: 2.4.2
pytz: 2015.7
blosc: None
bottleneck: 1.0.0
tables: 3.2.2
numexpr: 2.4.4
matplotlib: 1.4.3
openpyxl: None
xlrd: 0.9.4
xlwt: None
xlsxwriter: 0.7.7
lxml: None
bs4: 4.3.2
html5lib: 0.999
httplib2: None
apiclient: None
sqlalchemy: 1.0.10
pymysql: None
psycopg2: None
Jinja2: None


In [11]: p.resample('Q', how='mean', axis=1, kind='period')
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<ipython-input-11-37b0fd9cdc67> in <module>()
----> 1 p.resample('Q', how='mean', axis=1, kind='period')

c:\python\envs\pandas-0.17\lib\site-packages\pandas\core\generic.pyc in resample(self, rule, how, axis, fill_method, closed, label, convention, kind,
loffset, limit, base)
   3641                               fill_method=fill_method, convention=convention,
   3642                               limit=limit, base=base)
-> 3643         return sampler.resample(self).__finalize__(self)
   3644
   3645     def first(self, offset):

c:\python\envs\pandas-0.17\lib\site-packages\pandas\tseries\resample.pyc in resample(self, obj)
     80
     81         if isinstance(ax, DatetimeIndex):
---> 82             rs = self._resample_timestamps()
     83         elif isinstance(ax, PeriodIndex):
     84             offset = to_offset(self.freq)

c:\python\envs\pandas-0.17\lib\site-packages\pandas\tseries\resample.pyc in _resample_timestamps(self, kind)
    285                 # downsample
    286                 grouped = obj.groupby(grouper, axis=self.axis)
--> 287                 result = grouped.aggregate(self._agg_method)
    288                 # GH2073
    289                 if self.fill_method is not None:

c:\python\envs\pandas-0.17\lib\site-packages\pandas\core\groupby.pyc in aggregate(self, arg, *args, **kwargs)
   3661         """
   3662         if isinstance(arg, compat.string_types):
-> 3663             return getattr(self, arg)(*args, **kwargs)
   3664
   3665         return self._aggregate_generic(arg, *args, **kwargs)

c:\python\envs\pandas-0.17\lib\site-packages\pandas\core\groupby.pyc in mean(self)
    764             self._set_selection_from_grouper()
    765             f = lambda x: x.mean(axis=self.axis)
--> 766             return self._python_agg_general(f)
    767
    768     def median(self):

c:\python\envs\pandas-0.17\lib\site-packages\pandas\core\groupby.pyc in _python_agg_general(self, func, *args, **kwargs)
   1223         # iterate through "columns" ex exclusions to populate output dict
   1224         output = {}
-> 1225         for name, obj in self._iterate_slices():
   1226             try:
   1227                 result, counts = self.grouper.agg_series(obj, f)

c:\python\envs\pandas-0.17\lib\site-packages\pandas\core\groupby.pyc in _iterate_slices(self)
   3637             slicer = lambda x: self._selected_obj[x]
   3638         else:
-> 3639             raise NotImplementedError("axis other than 0 is not supported")
   3640
   3641         for val in slice_axis:

NotImplementedError: axis other than 0 is not supported

```
