MultiThreaded Demo:

- fixing various race conditions throughout (usage of static vars, etc)
 - addition of a few lightweight mutexes (which are compiled out by default)
 - slight code rearrangement in discreteDynamicsWorld to facilitate multithreading
 - PoolAllocator::allocate() can now be called when pool is full without
     crashing (null pointer returned)
 - PoolAllocator allocate and freeMemory, are OPTIONALLY threadsafe
     (default is un-threadsafe)
 - CollisionDispatcher no longer checks if the pool allocator is full
     before calling allocate(), instead it just calls allocate() and
     checks if the return is null -- this avoids a race condition
 - SequentialImpulseConstraintSolver OPTIONALLY uses different logic in
     getOrInitSolverBody() to avoid a race condition with kinematic bodies
 - addition of 2 classes which together allow simulation islands to be run
   in parallel:
    - btSimulationIslandManagerMt
    - btDiscreteDynamicsWorldMt
 - MultiThreadedDemo example in the example browser demonstrating use of
   OpenMP, Microsoft PPL, and Intel TBB
 - use multithreading for other demos
 - benchmark demo: add parallel raycasting

src/BulletCollision/CollisionDispatch/btDefaultCollisionConfiguration.cpp

@@ -44,9 +44,7 @@ btDefaultCollisionConfiguration::btDefaultCollisionConfiguration(const btDefault
 //btDefaultCollisionConfiguration::btDefaultCollisionConfiguration(btStackAlloc*	stackAlloc,btPoolAllocator*	persistentManifoldPool,btPoolAllocator*	collisionAlgorithmPool)
 {
 
-	void* mem = btAlignedAlloc(sizeof(btVoronoiSimplexSolver),16);
-	m_simplexSolver = new (mem)btVoronoiSimplexSolver();
-
+    void* mem = NULL;
 	if (constructionInfo.m_useEpaPenetrationAlgorithm)
 	{
 		mem = btAlignedAlloc(sizeof(btGjkEpaPenetrationDepthSolver),16);
@@ -59,7 +57,7 @@ btDefaultCollisionConfiguration::btDefaultCollisionConfiguration(const btDefault
 	
 	//default CreationFunctions, filling the m_doubleDispatch table
 	mem = btAlignedAlloc(sizeof(btConvexConvexAlgorithm::CreateFunc),16);
-	m_convexConvexCreateFunc = new(mem) btConvexConvexAlgorithm::CreateFunc(m_simplexSolver,m_pdSolver);
+	m_convexConvexCreateFunc = new(mem) btConvexConvexAlgorithm::CreateFunc(m_pdSolver);
 	mem = btAlignedAlloc(sizeof(btConvexConcaveCollisionAlgorithm::CreateFunc),16);
 	m_convexConcaveCreateFunc = new (mem)btConvexConcaveCollisionAlgorithm::CreateFunc;
 	mem = btAlignedAlloc(sizeof(btConvexConcaveCollisionAlgorithm::CreateFunc),16);
@@ -193,9 +191,6 @@ btDefaultCollisionConfiguration::~btDefaultCollisionConfiguration()
 	m_planeConvexCF->~btCollisionAlgorithmCreateFunc();
 	btAlignedFree( m_planeConvexCF);
 
-	m_simplexSolver->~btVoronoiSimplexSolver();
-	btAlignedFree(m_simplexSolver);
-
 	m_pdSolver->~btConvexPenetrationDepthSolver();
 	
 	btAlignedFree(m_pdSolver);