Added Support for MP3 Audio

xdg-open does not work for Audio or Video - added Audio (specifically mp3 support) with Video support to be added soon
Updated audio support; added video

Updated the previous support for mp3, and added mp4 support. Needs other techniques as xdg-open will not work with audio/* and video/* mime types just yet
Added fix for video player visible on page pop

Detect when page is popped in order to reset video player visibility in FileInfo page when video is not being played
Update README.md
Bump version to 1.3
Bump version to 1.3
Merge pull request #1 from MFaroTusino/master

Add support for MP3 audio and MP4 video