Updating trunk with latest fixes on development branch

git-svn-id: https://plugins.svn.wordpress.org/placester/trunk@1037652 b8457f37-d9ea-0310-8a92-e5e31aec5664
Plugin screenshots moved to assets directory

git-svn-id: https://plugins.svn.wordpress.org/placester/trunk@1037657 b8457f37-d9ea-0310-8a92-e5e31aec5664