modified

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@884126 b8457f37-d9ea-0310-8a92-e5e31aec5664
Stop to prevent not to minify css files which has small size

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@884129 b8457f37-d9ea-0310-8a92-e5e31aec5664