I might later question this decision.
I liked how each "hardware" example was roughly one self-contained file. In the
"input_keyboard" case, this is no longer true.
This improves ttf-convert slightly:
- variable size glyphs
- initialize metrics for glyphs with zero-size bitmaps (e.g "space")
- move the font/serialization structures to a common header
The keyboard example includes keyboard layout data for the HSS-0129 (Japanese)
Sega Saturn keyboard.
