Making the plug-in respect W3TC settings for debugging caching

git-svn-id: https://plugins.svn.wordpress.org/rotatingtweets/trunk@1006176 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixing bug

git-svn-id: https://plugins.svn.wordpress.org/rotatingtweets/trunk@1006177 b8457f37-d9ea-0310-8a92-e5e31aec5664