allow to compile all demos when USE_GLUT is enabled in cmake

fix minor issue in ConcaveDemo (animation should be time-dependent)
remove COLLADA from the demos.

Demos/ConcaveDemo/ConcavePhysicsDemo.cpp

@@ -335,7 +335,7 @@ void ConcaveDemo::clientMoveAndDisplay()
 	if (m_animatedMesh)
 	{
 		static float offset=0.f;
-		offset+=0.01f;
+		offset+=dt;
 
 	//	setVertexPositions(waveheight,offset);