use freeglut by default under Windows

Demos/CcdPhysicsDemo/CcdPhysicsDemo.cpp

@@ -649,6 +649,7 @@ void	CcdPhysicsDemo::exitPhysics()
 	for (int j=0;j<m_collisionShapes.size();j++)
 	{
 		btCollisionShape* shape = m_collisionShapes[j];
+		m_collisionShapes[j] = 0;
 		delete shape;
 	}
 

Demos/CcdPhysicsDemo/main.cpp

@@ -29,5 +29,8 @@ int main(int argc,char** argv)
 	ccdDemo->getDynamicsWorld()->setDebugDrawer(&gDebugDrawer);
 
 
-	return glutmain(argc, argv,640,480,"Bullet Physics Demo. http://bullet.sf.net",ccdDemo);
+	glutmain(argc, argv,640,480,"Bullet Physics Demo. http://bullet.sf.net",ccdDemo);
+
+	delete ccdDemo;
+
 }