call to the convenience constructor requiring 
 * 2 parameter (ControlP5 instance, name)  
 *
 * 2) the Controller class has a set of empty methods that allow you to capture
 * inputs from the mouse including 
 * onEnter(), onLeave(), onPress(), onRelease(), onClick(), onScroll(int), onDrag()
 * These you can override and include functionality as needed.
 *
 * 3) use method getPointer() to return the local (relative) 
 * xy-coordinates of the controller
 *  
 * 4) after instantiation custom controllers are 