Made line comments work with whitespace delim and custom line terminator
Added a release note
BUG: rolling_count() and expanding_*() with zero-length args; rolling/expanding_apply() with min_periods=0
BUG: add 'import warnings' statement in panel.py (GH8152)
ENH: allow axis argument to append / move append code to generic.py (GH8295)
a simple test case for Panel, which raises NotImplementedError
move append in DataFrame to generic.py
moving test_append for DataFrame

moving test_append from frame.py #2

moving test_append from frame.py #3

moving test_append from frame.py #4
moving test_append for Series
a specific test case for DataFrame.append on `axis` argument