VIS: plot with `use_index=False` shouldn't plot the index name

Add test case

Add check for use_index before setting label

Add to release notes

Add test case for barplot

Add checks for use_index in bar plot

Missed merge conflict marker
ENH: serialization of categorical to HDF5 (GH7621)
Merge pull request #8812 from onesandzeroes/plotlabel

VIS: plot with `use_index=False` shouldn't plot the index name
BLD: fix odd usage of cython imports, xref (GH8602)
Merge pull request #8793 from jreback/cat_hdf

ENH: serialization of categorical to HDF5 (GH7621)
DOC: v0.15.2 edits
DOC: v0.15.2 typos
ENH: Timestamp: Support addl datetime classmethods

* `utcfromtimestamp`,`timestamp`, and `combine` now supported
* Closes #5351.