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.h

@@ -60,8 +60,7 @@ protected:
 	btPoolAllocator*	m_collisionAlgorithmPool;
 	bool	m_ownsCollisionAlgorithmPool;
 
-	//default simplex/penetration depth solvers
-	btVoronoiSimplexSolver*	m_simplexSolver;
+	//default penetration depth solver
 	btConvexPenetrationDepthSolver*	m_pdSolver;
 	
 	//default CreationFunctions, filling the m_doubleDispatch table
@@ -102,12 +101,6 @@ public:
 	}
 
 
-	virtual	btVoronoiSimplexSolver*	getSimplexSolver()
-	{
-		return m_simplexSolver;
-	}
-
-
 	virtual btCollisionAlgorithmCreateFunc* getCollisionAlgorithmCreateFunc(int proxyType0,int proxyType1);
 
 	///Use this method to allow to generate multiple contact points between at once, between two objects using the generic convex-convex algorithm.