BUG: Period and Series/Index comparison raises TypeError

[sinhrks]

• tests added / passed
• passes git diff upstream/master | flake8 --diff
• whatsnew entry
  Period and Series/Index comparison raises TypeError if Period is on left hand side.

# OK
pd.Series([pd.Period('2011-01-01', freq='D')]) > pd.Period('2011-01-01', freq='D')
#0    False
# dtype: bool

# NG
pd.Period('2011-01-01', freq='D') > pd.Series([pd.Period('2011-01-01', freq='D')])
# TypeError: Cannot compare type 'Period' with type 'Series'

[jreback]

lgtm. merge on green (or you can ping and i can).

[jreback]

thanks!