function Coordinate(x, y){
   if (x){
      this.x = x;
      if (y){
	 this.y = y;
      }
   }
}
Create a new Coordinate instance based on x and y grid data.
@class Coordinate is a class that can encapsulate location information.
@param {int} [x=0] The optional x portion of the Coordinate
@param {int} [y=0] The optinal y portion of the Coordinate