Create ZoomCamera.js

//////////////////////////////////////////////////////////////
// ZoomCamera.js
// Penelope iPhone Tutorial
//
// ZoomCamera is a simple camera that uses a zoom value to zoom 
// the camera in or out relatively from the default position set
// in the editor. It can snap to zoom values when moving closer
// to the specified origin and smoothly seeks when moving farther
// away. The camera checks for any objects that obstruct the view
// of the camera to the origin and snaps to be in front of those
// locations.
//////////////////////////////////////////////////////////////