Separated keyword sets for different subplot types of scatter_matrix.
Updated RELEASE.rst to note modifications closing #3267
TST: unit test for #3503
PERF: (GH3733) where block splitting now done in at most 2 blocks rather than

      item-by-item; add vb_suite tests for masking
BUG: _interleave now returns an lcd of int64 or 2 x the intsize if

     uints are seen
Merge pull request #3736 from jreback/mask_slow

PERF: speed up where operations when splitting blocks (GH3733)
TST: Fix assert_almost_equal error message

Most tests are of form assert_almost_equal(result, expected).  Verbose
error message was treating its first argument as expected, this is now
fixed.
Merge pull request #3694 from pydata/PR-test-3503

Test to verify/fix behavior in #3503
REF: promote parser.pyx into top level
CLN: remove sandbox cruft
BUG: fix _parser->parser import (sorry)
BUG: fix tokenizer bug with \r line terminator and quoted fields. closes #3453
Merge PR #3673
BUG: fix failing scatter matrix test
BUG: (GH3740) Groupby transform with item-by-item not upcasting correctly
BUG: ensure float into function of series transform when item-by-item

     downcast result if needed
Merge pull request #3743 from jreback/groupby_int

BUG: (GH3740) Groupby transform with item-by-item not upcasting correctly
Merge pull request #3737 from jtratner/fix-assert-almost-equal

TST: Fix assert_almost_equal error message