Homescreen: Scroll applist immediately on touchmove

touchmove and touchend causes two paints. This avoids delay
between these two paints and starts scroll immediately on touchmove.
This also delays additional paints at the end of scroll.

Change-Id: I9e2c7f32d0667c5bd3d65700a7f8755cfc2b8701

Conflicts:

	apps/homescreen/js/grid.js