Implemented touch behavior (issue #10)

1. Added touch event listeners for **touchstart**, **touchmove** and **touchend**
2. Due to the difference in event API, I made an object called `moveObj` that has the proper `pageX` and `pageY` attributes
3. Switched all `e.pageX` and `e.pageY` call by `moveObj.pageX` and `moveObj.pageY` respectively.