New gpuMultiThreaded config option to enable/disable multi-threaded rendering (enabled by default, disabling it reverts to previous behaviour).
Other rendering optimisations:
- texture uploads now only affect appropriate region in the texture sheet, rather than uploading the whole sheet each time
- performance of clearing the model caches has been improved
New Alt+O key input added to toggle outputting of frame timings for debugging purposes.
- Model LUT now capable of differentiating between texture offset states (linked list of different texture offsets for each model address).
- Removed texOffset uniform attribute from vertex shader -- no longer needed.
