TEST: add basic postgresql tests

TEST: add postgresql to travis
TEST io.sql: sqlite tests to seperate class

One base class for tests with sqlalchemy backend. So test classes
for mysql and postgresql don't have to overwrite tests that are
different for sqlite.
ENH: support per-axis, per-level indexing with loc[]

CLN: add comments in indexing code

CLN: comment out possibly stale kludge fix and wait for explosion

CLN: Mark if clause for handling of per-axis tuple indexing with loc

PERF: vectorize _spec_to_array_indices, for 3-4x speedup

PERF: remove no longer needed list conversion. 1.4x speedup
CLN: move indexing loc changes to index.py
TST: tests for per_axis_per_level_getitem
ENH: add core/indexing.py/_getitem_nested_tuple to handle the nested_tuple cases for partial multi-indexing
ENH: allow core/index/_get_loc_level to deal with a slice indexer for a particular level
ENH: remove get_specs/specs_to_index -> replace with get_locs, to directly compute
     an indexer for a multi-level specification
ENH: allow per_axis, per_level multiindex setting

TST: better error messages when levels are not sorted with core/index/get_locs

ENH: add boolean indexer support on per_axis/per_level

BUG: handle a multi-level indexed series passed like with a nested tuple of selectors
     e.g. something like: s.loc['A1':'A3',:,['C1','C3']]
DOC: v0.14.0 and indexing doc updates for mi slicing

DOC: release notes and issues for mi_slicing
BUG: Raise a TypeError when trying to assign with a rhs of a multi-index of differeing levels (GH3738)
API: add in IndexSlice indexer shortcut
ENH: make it possible to pass keyword argument to .loc
ENH: allow the axis keyword to short-circuit indexing
BLD: add support for pytables 3.1
BLD: update 3.3 build for numexpr 2.3
Merge pull request #6268 from jreback/pytables_3.1

BLD: add support for pytables 3.1
Merge pull request #6301 from jreback/mi_indexing

ENH: per axis and per level indexing (orig GH6134)
Merge pull request #6316 from jorisvandenbossche/sql-postgresql-tests

TEST: add basic postgresql tests
BUG: Bug in setting complex dtypes via boolean indexing (GH6345)
Merge pull request #6347 from jreback/complex

BUG: Bug in setting complex dtypes via boolean indexing (GH6345)
TST: update for windows tests failures