Added a renderer closing procedure.

- Programs using Renderer RendererActor and actors can now close
without sys.exit, merely by calling system.shutdown on the ActorSystem.
- The SurfaceJogl destroy procedure was reworked, mainly you do not
have to call win.destroy explicitly.
- The RendererActor now has a closing procedure in two times -> first
it sends Closed, then it expect a call to Stop (which do proper
stopping of the surface and cleans resources) then it sends a Stopped
message as confirmation.