Added pomf.se WebM and MP4 support

Added support for WebM and MP4 video formats for the website http://pomf.se

Request from Reddit: http://redd.it/293ee6
It will show the video player but the video won't load. (In Opera)

It could be possible to implement a detection system so it will only show the inline video player if the browser supports the file format. Maybe even add text behind the video saying `[Unsupported File Format]` for the videos the browser doesn't support like it does with duplicated images.