DOC: clean-up docstrings of sql
DOC: fix sql docs (write example data to database)
clarified to_excel and read_excel

as discussed in issue GH6260
. io.rst: added a paragraph explaining the difference in behaviour from
0.12
. excel.py: added docstring for has_index_names
thanks to jmcnamara and jorisvandenbossche
BLD: import error on py2.6 for print_versions
Merge pull request #6302 from iled/doc

DOC: clarified to_excel and read_excel (GH6260)
Merge pull request #6298 from jorisvandenbossche/sql-docstring

DOC: clean-up docstrings of sql + fix doc build
Added assert_numpy_array_equals to make assert statments in this
be easy to understand.
Merge pull request #6315 from KTAtkinson/issue_6175

BUG: #6175 Got rid of assert_ statements in test_algos.py
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
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