Update admin styling

git-svn-id: https://plugins.svn.wordpress.org/ml-slider/trunk@890561 b8457f37-d9ea-0310-8a92-e5e31aec5664
Add line height back to captions

git-svn-id: https://plugins.svn.wordpress.org/ml-slider/trunk@890562 b8457f37-d9ea-0310-8a92-e5e31aec5664
Moved flexslider styling into flexslider.css

git-svn-id: https://plugins.svn.wordpress.org/ml-slider/trunk@890564 b8457f37-d9ea-0310-8a92-e5e31aec5664