Merge pull request #3093 from jreback/perf_indexing

PERF: added convert=boolean to take to enable negative index conversion
ENH/CLN: refactor of common code from frame/panel to generic.py
         axis creation routines now commonized under _setup_axes
ENH: more methods added

PERF: was missing multi-take opportunity in reindex
      was incorrectly passing to com._count_not_none
      doing an extra copy in certain cases
BUG: reindex with called with no args will by default return a copy (fixed bug)
ENH: moved filter and added axis arg
     moved where,mask,align

TST: make reindex benchmarks longer

CLN: fixed up names for creation in panelnd.py

DOC: minor release notes changes
DOC: release notes for this to 0.12.0
MERGE