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/Gimpact/btGImpactShape.h

@@ -722,17 +722,8 @@ public:
 		m_box_set.setPrimitiveManager(&m_primitive_manager);
 	}
 
-
-	btGImpactMeshShapePart(btStridingMeshInterface * meshInterface,	int part)
-	{
-		m_primitive_manager.m_meshInterface = meshInterface;
-		m_primitive_manager.m_part = part;
-		m_box_set.setPrimitiveManager(&m_primitive_manager);
-	}
-
-	virtual ~btGImpactMeshShapePart()
-	{
-	}
+    btGImpactMeshShapePart( btStridingMeshInterface * meshInterface, int part );
+    virtual ~btGImpactMeshShapePart();
 
 	//! if true, then its children must get transforms.
 	virtual bool childrenHasTransform() const
@@ -742,19 +733,8 @@ public:
 
 
 	//! call when reading child shapes
-	virtual void lockChildShapes() const
-	{
-		void * dummy = (void*)(m_box_set.getPrimitiveManager());
-		TrimeshPrimitiveManager * dummymanager = static_cast<TrimeshPrimitiveManager *>(dummy);
-		dummymanager->lock();
-	}
-
-	virtual void unlockChildShapes()  const
-	{
-		void * dummy = (void*)(m_box_set.getPrimitiveManager());
-		TrimeshPrimitiveManager * dummymanager = static_cast<TrimeshPrimitiveManager *>(dummy);
-		dummymanager->unlock();
-	}
+    virtual void lockChildShapes() const;
+    virtual void unlockChildShapes()  const;
 
 	//! Gets the number of children
 	virtual int	getNumChildShapes() const