added readme

This program compiles on linux and mac (it may also work on windows, though

it was not tested). It requires:

-qmake,

-make,

-g++ (maybe other compilers work),

-Qt 4,

-OpenGL 3.1 or GLew 1.5.2,

-libnetpbm, and

-glut or freeglut.

To build, simply run qmake and make.