Adjusted frequency and amount of cloud on Earth
Changed the rotation axis of background space
Packed precomputed gradients into smaller texel size

OpenGL pixel format GL_RGBA2 is perfect for precomputed gradients but
WebGL doesn't have it. So I used WebGL version of GL_RGBA4 to pack data
as tightly as possible, saving at least 16MB of GPU memory.
Instread of passing parameter of a desired order to FBM(), now caller must explicitly specify the order in function name
Merge branch 'master' into performance