Fix video restart on toggleFullscreen

Problem:
When the video is started, if we pass on fullscreen mode, the video
restart at 00:00.

Fix:
We save the position timing BEFORE stopping the video, we pass in
fullscreen, we
play the video, then we set the position timing of the previous session
video on the current video

var pos = vlc.input.position;
vlc.playlist.stop();
//fullscreen
vlc.playlist.play();
vlc.input.position = pos;

Tested:
Chrome
Firefox
Windows 64 bit