Inlined some method calls in me.TMXOrthogonalRenderer.drawTileLayer

A couple of method calls in drawTileLayer were creating garbage unnecessarily, i.e. `me.Vector2d` objects which were immediately released.  Inlining these methods gives us slightly less elegant code but saves us some cycles on garbage collection.  
This set of changes is definitely not safe, because it returns a reference to the shape, where code may then attempt to manipulate the position vector after it has been pushed into the pool.