BLD: update submit_cache.py to to properly submit caches to iron.io
ENH: cythonize groupby count
VB: add a vbench for groupby count
BUG: numeric_only must be False for count
ENH: add counts for object dtype
TST: add groupby count object dtype test
CLN: add count test
TST: add timedelta64 agg test
ENH: add datetime64 cythonized count
TST: add timedelta64 count test
CLN/TST: separate tests
CLN: no need to cast since we do not have object arrays anymore
RVT: revert change to add timedelta sum test
CLN: remove explicit casting in cython