Double tap to zoom in feature implemented.

I created a zoom in animation.
Also I modified the tap delegate, so that it now supports both single and double taps: the user can decide what to do on each callback.
Modified the tap msg sent back to the handler. It not has the property noOfTouches so that the developer knows how many taps the user issued.
Implemented the `zoomOnHeight: toPoint: time:];` method. 
Also added the zoomInOnDoubleTap property..

The user can now decide wether he wants double tap to zoom in or not.. Default is FALSE so as to not mess with pre-existing projects.

I hope you enjoy..!