Fix imshow edges#8300

Closed

tacaswell wants to merge 3 commits intomatplotlib:v2.0.xfrom

tacaswell:fix_imshow_edges

Commits on Mar 14, 2017

MNT: simplify creation of output array
tacaswell
committed

Commits on Mar 15, 2017

TST: minor tweaks to tests
tacaswell
committed

Commits on Mar 20, 2017

API: tweak how masking from agg alpha channel is handeled
tacaswell
committed