v0.12.0

• Use a constant shadow bias and switch shadows to using front faces
• Add support for calculating the blue/Z channel of a normal map in the shader
• Fix IBL reflection vector (was using view-space vector instead of world-space)
• Fix 330 shaders being used when not requested
• Some fixes for WebGL (GLSL ES)
• Fix duplicate definition in tonemap.frag that could cause compile errors
• Fix potential compile issue with non-330 shaders when calculating shadow contributions
• Explicitly disable sRGB for HDR framebuffer
• Fix IBL lagging behind by a frame