Some fixes

Hi dude!,

I'm adding your plugin into a game I'm testing and have to say it was very useful. Still it needed some amendments to make work as expected. Thought you may want to merge my changes:

-Sesitivity change to make it a bit easier to use
-Translation of the clientX and clientY points in the touch for when the target element has a screen offset.
-Change vertical direction (they were upside down)