for revert button of image optimization

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@1004572 b8457f37-d9ea-0310-8a92-e5e31aec5664
revert button has been added

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@1004573 b8457f37-d9ea-0310-8a92-e5e31aec5664
image optimization list

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@1004574 b8457f37-d9ea-0310-8a92-e5e31aec5664