csqc sound builtins.

[Shpoike]

vkquake's csqc implementation lacks the sound:8 builtin (defined as PF_Fixme in pr_cmds.c), while pointsound exists it lacks channel replacements which makes stuff awkward.

additionally localsound:177 is missing (not to be confused with ssqc's ex_localsound:0 from the rerelease), making it harder to provide sound effects in csqc menus etc.