BUG: allow DataFrame constructor to accept more list-like objects, e.g. list of
    `ollections.Sequence and array.Array objects (GH3783 and GH42971)
TST: explicity tests for iterator/generator types in DataFrame/Series construction

ENH: add generator support in DataFrame constructor
Merge pull request #4829 from jreback/seq

ENH/API: allow DataFrame constructor to better accept list-like collections (GH3783,GH4297)
BUG: Fix copy s.t. it always copies index/columns.

Only copies index/columns with `deep=True` on `BlockManager`. Plus some
tests...yay!
Change copy to make views of indices.

Requires changing groupby to check whether indices are identical, rather
than comparing with `is`. Plus add tests for name checks through
everything.