nil out CurrentHedgehog in FreeModule, add a test for nil'd CurrentHedgehog in DelCI since I'd still like to use DeleteGear for the other stuff it does. Move some variable initialiasations in AI Misc to hopefully avoid some uninit val errors.

void fpcrtl_halt(int num) {
    __coverity_panic__();
}

int fpcrtl_abs(int num) {
    return num >= 0 ? num : -num;
}