Merge pull request #8460 from immerrr/preserve-index-names-when-reindexing

BUG: fix Index.reindex to preserve name when target is list/ndarray
WIP: searchsorted implementation
TST: complex ops test correction
Merge pull request #7447 from cpcloud/pd-searchsorted

WIP: searchsorted implementation
Closes #6852. Dataframe memory usage methods implemented.
Merge pull request #7619 from asobrien/df-mem-info

ENH: dataframe memory usage
BUG: fix Index.reindex to preserve type when target is empty list/ndarray

TST: check index/columns types when doing empty loc/ix tests

CLN: don't _ensure_index in NDFrame._reindex_axes, it is done in
     Index.reindex