Redux 1.0

Performance improvements:

• Cloud shadows are rendered using the depth buffer instead of re-rendering most of the scene's geometry with a projector
• Celestial shadows are also rendered using the depth buffer instead of re-rendering most of the scene's geometry with a projector
• All the particles in a volumetric cloud layer are rendered at once in a single draw-call, instead of one draw-call per particle, saving CPU time
• One MeshRenderer and one GameObject per volumetric layer instead of one per particle
• Volumetric particles are rendered at 1/4 the screen resolution then upsampled with a depth-aware filter and composited into the scene, saving GPU power