Resample docstring default values changed

This docstring seems better, since TimeGrouper specifies it [that way][1] too:

[1]: https://github.com/pydata/pandas/blob/master/pandas/tseries/resample.py#L27
Remove confusing default val hints from docstrings
BLD: speed up test_perf.sh
ENH: Pass **kwargs through to matplotlib .scatter()
Merge pull request #3159 from danbirken/kwargs_to_scatter_plot

ENH: Pass **kwargs through to matplotlib .scatter()
DOC: Add more detailed description of commit prefixes
Merge pull request #3160 from danbirken/commit_prefix_explain

DOC: Add more detailed description of commit prefixes
BUG: GH3163 fixed to_csv with a boundry condition issue at the chunksize break
BUG/CLN: Exception in HDFStore are now ValueError or TypeError
         A table will now raise if min_itemsize contains fields which are not queryables
Merge pull request #3166 from jreback/GH3163

BUG: GH3163 fixed to_csv with a boundry condition issue at the chunksize break
Merge pull request #3167 from jreback/hdf_error2

BUG/CLN: Exception in HDFStore are now ValueError or TypeError
Merge pull request #3085 from kermit666/patch-3

Resample docstring default values changed
SCR: test_perf can save results frame to pickle file, -d