DOC: beef up tutorial section. GH5837
Merge pull request #6095 from y-p/PR_tuts

DOC: beef up tutorial section. GH5837
Merge pull request #6089 from jreback/apply_warn

DOC: remove warnings in panel.apply docs (GH6087)
BUG: not converting scalars properly to M8/m8 on assignment (GH6079)
CLN: removed need for SNDArray ; simplied SeriesGroupber / SeriesBinGrouper
TST: skip read_dta2 on non-little endian
BUG: rework object inferernce with NaN as the first element in an array
BUG: convert datetime like better from list-of-lists
BUG: make rank of M8 work via object algos