code: function Touch(target, identifier, pos, deltaX, deltaY) {
          deltaX = deltaX || 0;
          deltaY = deltaY || 0;
  
          this.identifier = identifier;
          this.target = target;
          this.clientX = pos.clientX + deltaX;
          this.clientY = pos.clientY + deltaY;
          this.screenX = pos.screenX + deltaX;
          this.screenY = pos.screenY + deltaY;
          this.pageX = pos.pageX + deltaX;
          this.pageY = pos.pageY + deltaY;
      }
docs: create an touch point
  @constructor
  @param target
  @param identifier
  @param pos
  @param deltaX
  @param deltaY
  @returns {Object} touchPoint