Move screenshots to assets directory

git-svn-id: https://plugins.svn.wordpress.org/comment-contest/trunk@985408 b8457f37-d9ea-0310-8a92-e5e31aec5664
Oops wrong directory. Icon plugins go into the right assets directory

git-svn-id: https://plugins.svn.wordpress.org/comment-contest/trunk@985415 b8457f37-d9ea-0310-8a92-e5e31aec5664