psrdnoise: 3-D demos

Various example uses of the 3-D version of psrdnoise.

• Plain 3-D noise on a sphere, with animation
• Fractal sum with displacements, Flow Noise style
• Yellow sun, or something
• Red sun, with a different look
• A sphere with liquid on it
• A sphere with displacement and bump mapping, both using the analytical gradient of psrdnoise to recompute normals
• A really busy sphere with no other purpose than to use noise a lot
• Dark energy core, a nod to our mapping of gradients
• A smoke plume, or at least our attempt at one.