mElite 08: Let's add texture on our planet

Download sgi.h and sgi.c. In this files some utilities for handling textures are implemented.

Our new version of mElite uses texture mapping. New features to add (emphasised in the the proposed solution code with the word "NEW" in the comments) are:

>>Here<< is a possible solution. You can compile it with this new Makefile. Obviously, as for the previous version, for compiling and running you need sgi.h, sgi.c, sun.sgi, earth.sgi, and the older files camera.cpp, camera.h, coriolis.h, eliteutils.h, and eliteutils.c in the same directory.