fix shaders, so that shadowed and non-shadowed are matching
fix registerGraphicsUnitSphereShape API (level of detail), support textured sphere too
add support for textured cube
add start for a Tutorial.cpp
add crude screenshot facility (using F1 key), it can also be used for debugging
start with shadows using shadowmap, not working yet
add experimental 'ignore' body index in raycast, using b3HitInfo.m_m_hitResult2