Add dashboard screenshot

git-svn-id: https://plugins.svn.wordpress.org/affilizr/trunk@942817 b8457f37-d9ea-0310-8a92-e5e31aec5664
Add installation screenshot

git-svn-id: https://plugins.svn.wordpress.org/affilizr/trunk@942818 b8457f37-d9ea-0310-8a92-e5e31aec5664
Add screenshots

git-svn-id: https://plugins.svn.wordpress.org/affilizr/trunk@942819 b8457f37-d9ea-0310-8a92-e5e31aec5664