updated docs

git-svn-id: https://plugins.svn.wordpress.org/ads-campaigns/trunk@911211 b8457f37-d9ea-0310-8a92-e5e31aec5664
removed unnecessary screenshots

git-svn-id: https://plugins.svn.wordpress.org/ads-campaigns/trunk@911212 b8457f37-d9ea-0310-8a92-e5e31aec5664