DOC: remove an obsolete file
Merge pull request #2766 from argriffing/remove-obsolete-docs

DOC: remove doc/seps/technology-preview.rst
BUG: handle array_like input in stats.circ* functions.  Closes gh-2062.

Also add test for empty input, return nans.
Merge pull request #2802 from rgommers/issue-2062-circfuncs

BUG: handle array_like input in stats.circ* functions.  Closes gh-2062.
BLD: Fix msvc error C2036: 'void *' : unknown size

(cherry-picked from 827083acfa)