UpdateManager looks for version_os instead of just version

Also cleaning up memory in PlaylistWidget::RemoveItem
Merge branch 'master' of github.com:u8sand/Baka-MPlayer
Made screenshot status message
Moved parsing of screenshot-template to mpvhandler

It started to show up all over the place so I consolidated it into mpvhandler on loading settings. The only place it's repeated is in preferences dialog which should be modified to not write directly to settings as it is now.

Fixed up the screenshot message.