We can now do this since the entire scene and all objects within it are now successfully gc'd at the end of these tests.
This greatly improves the time taken to run each test (by reducing teardown time, not the time to actually do the test work that we're interested in).
Slightly simplifies config read in Scene constructor to help facilitate this.
This illustrates that references to Scene, SOG, etc. are not currently being released when a stress test ends (or at regression test end in general).
This means even the current stress tests take much more memory than they need, a problem that will have to be addressed.
