Rough first pass at adding a graphical mode
Moved code for frontends into their own source files. renamed
gameoflife.c to main.c . Moved generate and wait() functions to algo.c
Updated README to include libglfw-dev requirement. Added lGL to LIBS
in Makefile for OpenGL linking
Set Vblank to False so graphical display doesn't stutter on systems
with Vblank enabled
Added fullscreen option for graphical mode
Cleaned up CLI argument parsing code. Was a hot mess
Renamed algo.c/h to backend.c/h for clarity
Removed uneeded includes