Bump bundled video.js to v3.2.3 (#512)

Bump bundled video.js to v3.2.3 (#512)

There is nothing inherently wrong with the currently bundled version,
but the last one was uploaded in March 2012 and there have been
upstream releases since. So bump to the latest available release 3.2.3.

Might help with the reported issue 512 of an unresponsive video player.

Do note that the Flash fallback option is removed. If we decide
this should be added it is easy to add it back.

We still use our own customized theme.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>