phase out Adafruit graphics library

[RiedleroD]

To do:

• [ ] replace all usages of the library besides drawPixel
• [ ] replace drawPixel usages by implementing custom function (without framebuffer this time)
  • [ ] hotfix games that needed the framebuffer
• [ ] remove library from compilation and Readme

this will make compilation faster, ROM usage …lesser, and free up most of the RAM, since ~50% is currently used by the framebuffer.

(stalled by #27 #29 and #3)