better input validation on `fill_between`#7817

Merged

anntzer merged 4 commits intomatplotlib:masterfrom

samsontmr:fix-#7510

Jan 18, 2017

Commits on Jan 13, 2017

Add input validation for fill_between and fill_betweenx and unit tests
samsontmr
committed

Commits on Jan 14, 2017

Commits on Jan 16, 2017

Update exception string to use %r for formatting
samsontmr
committed