Fix accidental dismiss onClick

Related with #42 but not the same.

The line [ContextualUndoListViewTouchListener:L163](https://github.com/nhaarman/ListViewAnimations/blob/master/library/src/com/haarman/listviewanimations/itemmanipulation/contextualundo/ContextualUndoListViewTouchListener.java#L163) have a problem: the clicks. This PR checks that `Math.abs(DeltaX) > mSlop`.