Fix touch event cap and increase the cap

If you have more than 5 touch events (like 10 fingers on iPad), <code>event.touches.length</code> = 6 but the last index is empty and will break code that doesn't handle a non-existent event object. I've also increased the cap from 5 to 16 (hey, we have 10 fingers! plus a safety buffer).

Note: Sorry I have the iOS 7 bug included in this since I didn't branch it.