- stop threads when exiting demo that uses multi threading

- improved friction model for parallel solver (align the friction direction with projected velocity, unless the projection is close to zero (only then use 2 arbitrary axis orthogonal to contact normal)

Demos/CcdPhysicsDemo/CcdPhysicsDemo.h

@@ -25,6 +25,7 @@ class btCollisionDispatcher;
 class btConstraintSolver;
 struct btCollisionAlgorithmCreateFunc;
 class btDefaultCollisionConfiguration;
+class Win32ThreadSupport;
 
 ///CcdPhysicsDemo shows basic stacking using Bullet physics, and allows toggle of Ccd (using key '1')
 class CcdPhysicsDemo : public DemoApplication
@@ -37,6 +38,10 @@ class CcdPhysicsDemo : public DemoApplication
 
 	btCollisionDispatcher*	m_dispatcher;
 
+	Win32ThreadSupport*		m_threadSupportCollision;
+
+	Win32ThreadSupport*		m_threadSupportSolver;
+
 	btConstraintSolver*	m_solver;
 
 	btCollisionAlgorithmCreateFunc*	m_boxBoxCF;