code: public Triangle find(Vector3 p, Triangle start) {
  		if (start == null)
  			start = this.startTriangle;
  		Triangle T = find(start, p);
  		return T;
  	}
docs: finds the triangle the query point falls in, note if out-side of this
  triangulation a half plane triangle will be returned (see contains). the
  search starts from the the start triangle
  
  @param p
  query point
  @param start
  the triangle the search starts at.
  @return the triangle that point p is in..