Copied autoplay attribute from video xmoudle to videoalpha. Now students will have the video autoplaying, and in Studio it will be pause by default.

common/lib/xmodule/xmodule/js/src/videoalpha/display/video_player.coffee

@@ -99,7 +99,7 @@ class @VideoPlayerAlpha extends SubviewAlpha
     @video.log 'load_video'
     if @video.videoType is 'html5'
       @player.setPlaybackRate @video.speed
-    unless onTouchBasedDevice()
+    unless onTouchBasedDevice() or $('.video:first').data('autoplay') == 'False'
       $('.video-load-complete:first').data('video').player.play()
 
   onStateChange: (event) =>