add test for VR HUD/sub-titles
fix issue in previous commit, partial string use %.8s not %8.s
use long long int in b3Clock
fix warning/error in pointer alignment in serialization
Fix pybullet Windows compilation.
(thanks to bkeys/https://github.com/bulletphysics/bullet3/pull/687)
use DIRECTLY_UPDATE_VELOCITY_DURING_SOLVER_ITERATIONS by default for now,
until we find the issue with some failing test cases in btMultiBody
fix a crashing issue in MyMultiBodyCreator.cpp (uninitialized variable)
disable excessive debug printf in URDF2Bullet
