-Baked recovery records into play queue items.

-Added previous and next button on main video player.
-Reverted double tap to seek for popup and main video players.
-Improved shuffling to use recovery record.
-Changed shuffling to place current playing stream to top of queue.
-Fixed exception when removing last item on queue.
-Changed fast forward and rewind button to previous and next on background notification.
-Changed background notification to not update when screen is off and update immediately when screen is turned back on.
-Removed unused intent strings.
-Changed "Append" to "Enqueue" for append text.

app/src/main/java/org/schabi/newpipe/util/NavigationHelper.java

@@ -77,12 +77,8 @@ public class NavigationHelper {
                                          final Class targetClazz,
                                          final PlayQueue playQueue,
                                          final int maxResolution,
-                                         final int restoringIndex,
-                                         final long startPosition,
                                          final float playbackSpeed) {
         return getPlayerIntent(context, targetClazz, playQueue, maxResolution)
-                .putExtra(VideoPlayer.RESTORE_QUEUE_INDEX, restoringIndex)
-                .putExtra(BasePlayer.START_POSITION, startPosition)
                 .putExtra(BasePlayer.PLAYBACK_SPEED, playbackSpeed);
     }