Makefile:
- Don't set DATA, we're no longer embedding files from there directly
- Add folders from GRAPHICS to VPATH. This is how make finds the source files
- Add PNGFILES variable containing all png files from GRAPHICS folders
- Add png files to OFILES with extension changed to rgb.o
- Add rule to create .rgb.o fromn .rgb using normal bin2o macro
- Add rule to create .rgb from .png using imagemagick
source/main.c
- the extension has changed to .rgb so the header is now <filename>_rgb.h and the variables end in _rgb
