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
ENH: added numexpr support for where operations
     implemented internals/where in numexpr
Merge pull request #3085 from kermit666/patch-3

Resample docstring default values changed
DOC: minor edits in io.rst
SCR: test_perf can save results frame to pickle file, -d
BUG: Fix the rename for Series and DataFrame, #3165
TST: Test to_csv in more cases and faster
TST: add test for test in test_testing
BUG: check_less_precise in assert_almost_equal with val=float throws exception
DOC release notes add assert_frame_equal checks index and column names
Merge pull request #3172 from jreback/docs

DOC: minor edits in io.rst / cookbook.rst
Merge pull request #3174 from hayd/assert-frame-equal-doc

DOC release notes add assert_frame_equal checks index and column names
Merge pull request #3175 from waitingkuo/fix-rename

BUG: Fix the rename function for Series and DataFrame, #3165
DOC: better error message on ndarray construction, GH3105

CLN: refactor to put all block manager creation calls into internals.py
     so to wrap with invalid constructions
TST: now py3 compatible
Merge pull request #3131 from jreback/GH3105

DOC: GH3105 better error message on ndarray construction
TST: resample test custom_grouper haveing dtype comp error on 32-bit
      from GH2763 changes
Merge pull request #3176 from jreback/resample_dtype

TST: resample test custom_grouper haveing dtype comp error on 32-bit
PERF: groupby transform
PERF: added vb_suite test for groupby_transform
      added to RELEASE.rst, issue GH2121