Fix PHP warning on incorrect library call.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@871627 b8457f37-d9ea-0310-8a92-e5e31aec5664
New utility function `addAdminNotices` for adding admin notices.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@871628 b8457f37-d9ea-0310-8a92-e5e31aec5664
Import media files from Tumblr Photo posts. Version bump to 0.7.8.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@871629 b8457f37-d9ea-0310-8a92-e5e31aec5664