Previously, on real hardware (emulator behaved fine), we would routinely
get repeat keys unless pressing the button very fast. This commit solves that.
This was mostly lifted from my "tihello" example, but it required significant
adjustments.
This commit also introduces a font management system. A lot of fonts are
available online, but sources aren't always clear so to avoid copyright
landmines, I re-created my first 5x7 font from scratch.
As it is now, this resulting ROM gets "Collapse OS>" to be displayed on the
LCD screen. Much work still left to do.
ref #41
