add option in COLLADA loading to specify client up axis (so that if client=Z and COLLADA =Z, upAxisTransform is identity,
while if client=Y and COLLADA=Y, upAxisTransform is identity etc)
remove various vertex format structures and use GLInstanceVertex from #include "OpenGLWindow/GLInstanceGraphicsShape.h"
btMultiBody::setupPrismatic takes an additional argument to allow a shift of inertia tensor, relative to the joint frame (link frame at q=0)
Fix WinXP GetTickCount64 with a typedef
Expose debug drawing mode/flags in UI (hot keys A,D,L,W for now, buttons later)
GLInstancingRenderer: tweak near/far planes to allow closer approach of camera
btDiscreteDynamicsWorld: enable debug drawing for btGeneric6DofSpring2Constraint
btMultiBodyDynamicsWorld: enable basic debug drawing for btMultiBody
btMultibody: allow center-of-mass shift for prismatic and fixed constraint
URDF import demo: add COLLADA .dae file support
add FiniteElementMethod demo, extracted from the OpenTissue library (under the zlib license)
don't crash if loading an invalid STL file
add comparison with Assimp for COLLADA file loading (disabled by default, to avoid library dependency)
Gwen: disable some flags that make the build incompatible
improve btMultiBody version of URDF reader (still work-in-progress)
enabled planar joint for btMultiBody (untested)
enable loading from relative path for .stl meshes
