ADD Option to use custom style sheet when sharing with external users


git-svn-id: http://svn.resourcespace.org/svn/resourcespace@5477 c08608d7-6e46-0410-86ca-f2a6f1370df5
add potx and key to unoconv extensions

git-svn-id: http://svn.resourcespace.org/svn/resourcespace@5478 c08608d7-6e46-0410-86ca-f2a6f1370df5
add ogv and webm to list of ffmpeg supported extensions. I recommend standardizing on a compile of ffmpeg from one source: https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

git-svn-id: http://svn.resourcespace.org/svn/resourcespace@5479 c08608d7-6e46-0410-86ca-f2a6f1370df5