- added linear limits to btGeneric6DofConstraint and made sure the linear axis are in local space of objectA

- use microseconds instead of milliseconds for deltatime

Demos/BspDemo/BspDemo.cpp

@@ -185,7 +185,7 @@ void BspDemo::clientMoveAndDisplay()
 {
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
 
-	float dt = m_clock.getTimeMilliseconds() * 0.001f;
+	float dt = m_clock.getTimeMicroseconds() * 0.000001f;
 	m_clock.reset();
 	m_dynamicsWorld->stepSimulation(dt);