timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
require the front-end to initialize rc_deffgcolor and rc_defbgcolor (both
new members), and override these only if RASTERCONSOLE_{FG,BG}COL are
set in the kernel configuration file.
Integrate patches from der Mouse (8-bit cleanliness, FULLSCREEN option,
SMALLFONT option).
The (MD) caller of rcons_init() is now responsible for initialising `rc_font'.
