BUG/API: df['col'] = value and df.loc[:,'col'] = value are now completely equivalent;
         previously the .loc would not necessarily coerce the dtype of the resultant
         series (GH6149)
DOC: reformat release.rst
Merge pull request #6159 from jreback/loc2

BUG/API: df['col'] = value and df.loc[:,'col'] = value are now completely equivalent
PERF: change Series indexing on multi-indexes to use a fast path
      like DataFrame uses
Merge pull request #6364 from jreback/ix_perf

PERF: change Series indexing on multi-indexes to use a fast path (GH5567)
TST: add failing test
CLN: remove unnecessary reassignment
BUG: fix nested dict bug