show a success message when the form builder page is saved with ajax

git-svn-id: https://plugins.svn.wordpress.org/formidable/trunk@865584 b8457f37-d9ea-0310-8a92-e5e31aec5664
added frm_encode_subject hook

git-svn-id: https://plugins.svn.wordpress.org/formidable/trunk@866333 b8457f37-d9ea-0310-8a92-e5e31aec5664
cleanup importing file type check

git-svn-id: https://plugins.svn.wordpress.org/formidable/trunk@868667 b8457f37-d9ea-0310-8a92-e5e31aec5664
allow importing new entries as draft

git-svn-id: https://plugins.svn.wordpress.org/formidable/trunk@869412 b8457f37-d9ea-0310-8a92-e5e31aec5664