Added VideoLibrary.Scan

Added VideoLibrary if statement to app.Router.prototype.scan() method.
Added VideoLibrary Scan button

Added "Video Library Scan" button to footer right dropup menu
Merge pull request #17 from amitkeret/20140331-amitk-videolibraryscan

Thanks! I have been meaning to get to that one.  Library scans don't need a router path as it doesn't render anything which ends up confusing history (back, refresh, etc).  All good for now though.