High Dynamic Range (HDR) rendering

Implemented High Dynamic Range rendering and the filmic tone mapping operator used in Uncharted 2, which mimics a filmic response curve for a more natural, film-like look. Bloom is added to objects that are very bright by performing a brightness filter pass before blurring the bloom texture. Diffuse textures and the LDR render target are now sRGB enabled so as to perform all shading in linear space and have gamma-correct output. Also, the light tuning has gone through a complete overhaul so as to leverage the new post-processing techniques.