MAINT: use assert_warns instead of a more complicated mechanism
MAINT: copypaste assert_warns from a newer numpy into scipy
MAINT: move a numpy compatibility function into its own file
MAINT: python 3 compatibility boilerplate
MAINT: small changes to address PR comments
PEP8: remove line continuation backslash
Merge pull request #3407 from argriffing/use-assert-warns

MAINT: use assert_warns instead of a more complicated mechanism