ENH: Add makePeriodPanel
BUG: (GH4853) Fixed Panel.shift/tshift to use freq.
TST: Added Panel.tshift test case
RST: Added to release notes
CLN: on top of dale-jung 4863, remove shift from series.py, move to generic.py
test case for #4872
BUG: tuple argument to isnull is considered same way as list #4872. Some unit test fixes

fix unit tests (#4872)

fixing unit test
change log entry for #4872
Merge branch 'master' of github.com:ssalonen/pandas

Conflicts:
	pandas/tests/test_common.py