ACTION_CANCEL was doing the same as ACTION_UP

This causes issues when a parent view tries to steal a MotionEvent using onInterceptTouchEvent (such as a DrawerLayout opening the side menu).

I've added an implementation for ACTION_CANCEL (looking at the latest romannurik code). This solves issue #65 on your issue tracker.

I hope I did this pull request right, I'm a bit new to the entire Github thing.