Share physics setup of BasicDemo between different graphics frameworks, see Demos\BasicDemo\BasicDemoPhysicsSetup.*
Plan is to do this for all Bullet demos.
Improve gwen performance and cursor navigation for tree control.
tweak shadowmap size
SimpleOpenGL3App::registerCubeShape accepts half extents
experiment with Midi controls in PairBenchmark to tune variables (will move it into a utility class, so every demo can easier use it in the future)
fix issue with broadphase, not initializing all pairs properly at pair array overflow
