Multithreaded Orion Engine

I’ve been working on making the Orion Engine more thread-safe. It’s desirable to be able to load a scene, while another is currently rendering. It turns out Direct3D 9 is not ‘thread-safe’. If you attempted to use our previous version 9 video driver from multiple threads, it could cause video driver crashes. Note however, starting with Direct3D 10, multiple threads are supported by default.