move parts of collision pipeline to shared header files (work-in-progress)
b3Solver -> pass pointer to source instead of 0 (was left over from a debugging session), thanks to David for the report
Break up clipHullHullConcaveConvexKernel into multiple stages, so it might 'fit' in Apple's OpenCL implementation
Implemented bvhTraversalKernel and findConcaveSeparatingAxis on CPU (debugging, possible future CPU version)