Fixed "play on xbmc" from youtube app

Sharing videos from youtube app to xbmcremote stopped working because
Intent.EXTRA_TEXT contained more than just the url and the url itself
changed to a short version (youtu.be/videoID)
Updated pattern with improved version

Found a better regex working regardless of the existence of protocol or "www" in the url and being more robust and readable in general. This regex also returns only one capturing group containing only the thing we are looking for, the video ID.
Tests: http://www.regexr.com/38m12