-Cleanup

git-svn-id: https://plugins.svn.wordpress.org/wp-booklet/trunk@849688 b8457f37-d9ea-0310-8a92-e5e31aec5664
-UI enhancements
-Added ability to show thumbnailed previews
-Added ability to upload PDFs
-Added ability to close booklets
-Added ability to upload images in bulk

git-svn-id: https://plugins.svn.wordpress.org/wp-booklet/trunk@849690 b8457f37-d9ea-0310-8a92-e5e31aec5664