FIX value_counts should skip NaT #7423
ENH dropna for value counts, fix tests for NaT
DOC add value_counts dropna to release notes
nanops pep8 fixes
PERF: addtl transform vbenches
WPI: fast tranform on DataFrame
BUG: Some offsets.apply cannot handle tz properly
FIX: Enable fixed width strings to be read from Stata 13 (117) files

Fixes a bug which prevented files containing fixed width string data from being read.  Stata 13 files also allow variable length strings, which are not supported in the current version, and an explicit exception regarding this type is now given.  Added tests which cover these cases, and Stata 13 format files. fixes #7360
FIX: Stata writer no longer ignores encoding when writing strings

The encoding was not used when writing strings. Fixes #7286
CLN: Simplify boxplot and modify its test
ENH: Cast ndarray-like datetime64 arrays to Index properly

It turns out that the ndarray-like arrays of dtype datetime64 were
not being properly cast to an Index, because -- due to a bug with
np.datetime64 -- calling np.asarray(x, dtype=object) if x is an
ndarray of type datetime64 results in an *integer* array.

This PR adds tests and a work around to pd.Index.__new__.

Related #5460
Merge pull request #7468 from shoyer/ndarray-like-to-index

ENH: Cast ndarray-like datetime64 arrays to Index properly
Merge pull request #7450 from bashtage/stata-13-strings

FIX: Enable fixed width strings to be read from Stata 13 (117) files
Merge pull request #7463 from jreback/merge_transform

PERF: performance gains in DataFrame groupby.transform for ufuncs (GH7383)
BUG: Bug in Panel.apply with a multi-index as an axis (GH7469)
Merge pull request #7474 from jreback/mi_array

BUG: Bug in Panel.apply with a multi-index as an axis (GH7469)
DOC: v0.14.1.txt fixes
Fix cache key collision and add test for cache key distinctness.
Merge pull request #7478 from ahlmss/TST7420

Fix cache key collision and add test for cache key distinctness.
BUG: copy certain interpolate arguments to ensure we can write to them;
closes #7295.