lightcone: prototype 2

This is the fourth release on increpare.com, a sequel to lightcone prototype 1 from a few days earlier. I haven't been able to get this one working; the page only provides a download link for the Haskell source code, which after several days of effort I was able to compile using a very old version of the Haskell compiler, but then gave up after running into issues linking the opengl binaries.