CLN: ipython expects None from _repr_html_ to signal no html repr GH5922
Merge pull request #6045 from y-p/PR_ipython_repr_html

CLN: ipython expects None from _repr_html_ to signal no html repr GH5922
DOC: minor doc edits
Merge pull request #6038 from Bklyn/master

Make -NaN and -nan default NA values
BUG: Regression in .get(None) from 0.12 (GH5652)
Merge pull request #6053 from jreback/get

BUG: Regression in .get(None) from 0.12 (GH5652)