Fix Undefined behavior

An array subscript is out of range (C99p6.5.6).
Fix minor annoyances.
Reorganize ocen_przedmiot().
Minor fixes.
Fix function types.
Move HTML_FUN declarations from merc.h to httpd.c.
Move GAME_FUN declarations from merc.h to gry.c.
Taking care of symbols defined in special.c
Taking care of symbols defined in palad.c
Taking care of symbols defined in necro.c
Taking care of symbols defined in qmagic.c
Taking care of symbols defined in magic.c
Taking care of symbols defined in act_wiz.c
Taking care of symbols defined in act_info.c
Taking care of symbols defined in act_comm.c
Taking care of symbols defined in act_obj.c
Taking care of symbols defined in act_move.c
Taking care of symbols defined in skr.c
Taking care of symbols defined in fight.c
Taking care of symbols defined in screen.c