Merge pull request #5704 from jreback/loc_astype

BUG: loc assignment with astype buggy, (GH5702)
Correct "sentinel" spelling.
TST add additional test from 2850
Merge pull request #5707 from dsm054/fix_sentinel_spelling

Correct "sentinel" spelling.
BUG: Bug in fillna with Series and a passed series/dict (GH5703)
CLN: clean up block validation for empty blocks
Merge pull request #5705 from jreback/series_fillna

BUG: Bug in fillna with Series and a passed series/dict (GH5703)
BUG: Bug in groupby transform with a datetime-like grouper (GH5712)
Add test for DataFrame.corrwith and np.corrcoef compatibility;
apparently failed once in 0.10.0.
BUG: correctly handle py2.6 datetime64 in groupers
Merge pull request #5713 from jreback/transform_bug

BUG: Bug in groupby transform with a datetime-like grouper (GH5712)
Merge pull request #5714 from dsm054/more_corrwith_tests

Add test for DataFrame.corrwith and np.corrcoef compatibility
DOC: fillna doc-string updated
TST: win32 test fixes (GH5711)
Merge pull request #5716 from pydata/winfix4

TST/DOC: close win32 tests issues (GH5711)
BUG: In a HDFStore, correctly handle data_columns with a Panel (GH5717)
Merge pull request #5718 from jreback/panel_hdf

BUG: In a HDFStore, correctly handle data_columns with a Panel (GH5717)
CLN: add diff to series/dataframe groupby dispatch whitelist
StataWriter: Replace non-isalnum characters in variable names by _ instead of integral represantation of replaced character. Eliminate duplicates created by replacement.
Merge pull request #5719 from gdraps/groupby-dispatch-2

CLN: add diff to series/dataframe groupby dispatch whitelist