fix HLS variant selection

This patch moves the (duplicated) stream selection code from dvdplayer/omxplayer to a separate input stream

This solves the following problems:

- Selecting variant when using pvr to manage the stream never worked (the path passed to DVDPlayer is pvr://) Perhaps affecting other as well? The problem is detailed [here](http://forum.xbmc.org/showthread.php?tid=169674&pid=1604524#pid1604524)
- Not working for https. This patch fixes the same as #3875