Fix Issue 712, related to NVIDIA CUDA check in CMakeLists.txt

Enable btGImpact raycast optimization, thanks to C0DEFACE, see Issue 664
Cull triangle/AABB for concave/heightfield shapes, thanks to Danny Chapman
fix btGetCpuCapabilities, thanks to Ian Ollman! See https://code.google.com/p/bullet/issues/detail?id=738

src/BulletCollision/CollisionDispatch/btConvexConcaveCollisionAlgorithm.cpp

@@ -80,6 +80,11 @@ void btConvexTriangleCallback::processTriangle(btVector3* triangle,int
 partId, int triangleIndex)
 {
 
+	if (!TestTriangleAgainstAabb2(triangle, m_aabbMin, m_aabbMax))
+	{
+		return;
+	}
+
         //just for debugging purposes
         //printf("triangle %d",m_triangleCount++);
 
@@ -90,6 +95,8 @@ partId, int triangleIndex)
 
 	//const btCollisionObject* ob = static_cast<btCollisionObject*>(m_triBodyWrap->getCollisionObject());
 
+	
+
 
 #if 0	
 	///debug drawing of the overlapping triangles