A small experiment on how to make menus.
Also features some small proof-of-concept (?) on how screen UIs could be tested.
Everything is contained in the tk directory. Fonts and icons are embedded in
the code.
User changes the menu.c file to make their menu (it is a rather immediate mode GUI).
User also provides set, clear pixel, and clear display functions, which
interface with the said display. Rest is listed in tk/usage.txt and
tk/using-bitmaps.txt.