This fixes the upostop-- test by auto-casting implicit constants to
unsigned (and it gives a warning for signed-unsigned comparisons
otherwise). The generated code isn't quite the best, but the fix for
that is next.
Also clean up the resulting mess, though not properly. There are a few
bogus warnings, and the legit ones could do with a review.
This has smashed the keydest handling for many things, and bindings, but
seems to be a good start with the new input system: the console in
qw-client-x11 is usable (keyboard-only).
The button and axis values have been removed from the knum_t enum as
mouse events are separate from key events, and other button and axis
inputs will be handled separately.
keys.c has been disabled in the build as it is obsolute (thus much of
the breakage).
