Moved adapter vendor check to its own func, added a global which could be used to fully disable the low latency system. Also added groundwork for the (future) PCL stats implementation.
CEngine::Frame() tends to return out early if we are ahead of frame time, and therefore need to sleep. In this particular engine, CEngine::Frame() returns true if it had actually executed an engine frame, else it returns false.
Therefore, we end up calling 'NvAPI_D3D_Sleep()' multiple times a frame, and thus causing a major loss in performance. Now we check if we have actually ran a frame (incrementing reflex frame if so). If the frame was not incremented, but 'GFX_RunLowLatencyFrame()' was called, it will not call 'NvAPI_D3D_Sleep()'.
Code has been tested and appears to work on my system (never called twice or more per frame). Needs more testing on other systems to make sure its good.
Propagated latency markers in an attempt to further reduce input latency. Code is pending rigorous testing on several systems, including systems powered by an AMD GPU to make sure we are not impacting performance on systems that does NOT support NVIDIA Reflex.
