Added images used by css files

git-svn-id: https://plugins.svn.wordpress.org/bookings/trunk@986178 b8457f37-d9ea-0310-8a92-e5e31aec5664
* Compatibility with WP version 4.0
* Load CSS and Javascript files from CDN for improved performance

git-svn-id: https://plugins.svn.wordpress.org/bookings/trunk@986179 b8457f37-d9ea-0310-8a92-e5e31aec5664