ENH: revamp null count supression for large frames in df.info()
Merge pull request #5974 from y-p/PR_info_max_info_rows

ENH: revamp null count supression for large frames in df.info()
ENH: make show_versions available in the top_level api
Merge pull request #5976 from y-p/PR_show_versions_to_the_top

ENH: make show_versions available in the top_level api
PERF: perf improvments in indexing with object dtypes (GH5968)
BUG: Bug in NaT comparison if a mixed datetime/np.datetime64 with NaT were passed (5968)
CLN: cleanup nat comparisons in tslib.pyx