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.  
I almost wonder if we should refactor the constructors to just accept x & y instead of a vector object. Let Rect handle the assignment.