rem: WMSortBag(WMBag *bag, int (*comparer)(void*, void*))
add: WMSortBag(WMBag *bag, int (*comparer)(const void*, const void*))
context: WMSortBag(WMBag *bag, int (*comparer)(void*, void*)){    qsort(bag->items, bag->count, sizeof(void*), comparer);}