Add admin/movies screen (needs 1988 first)
- admin_movies, admin_movies.html (new) - new Movies admin screen
- ffmpeg.png (new) - logo for admin screen
- movie::find_ffmpeg_version (new) - return version number and date of FFmpeg
- form_uploadify.html - change admin message if movie uploads are disabled
- gallery_event::admin_menu - added Movies link to Settings