Got the stone generation to be seamless. The problem was an out-of-order
line in noise.h.

-Peter Mawhorter
Some work on polishing up the demo, including the addition of some 3d-
simplex-noise-based caves. This initiated a push towards implementing
ambient occlusion, which has started with some cleaner neighborhood
accessor functions and revised exposure computation (which in turn
introduced at least one new bug). Thinking about having chunks overlap
each other to solve the problem of neighboring chunk data once and for
all.

-Peter Mawhorter