add qwe builtin extensions to qw-server. provide sv_progs_ext to control
the builtin mapping. valid values are "id", "qf" (our old static builtins),
"qwe"/"ktpro" (either works. for ktpro mod support) and "none" (no
mapping). any other value is equivalent to "none".
ranges can be used efficiently. move the auto-allocated builtins to
0x10000000-0x7fffffff. should be more than enough :)
use static builtin tables ("nul" terminated) instead of a series of
function calls to add builtins to a vm. should be more memory efficient.
