Added an additional '"Can't Use" flag to misc flags in item objects

* it makes the weapon object unusable in combat.

Updated gl_npcarmor script.
Edits to header files and hookscripts.md.

artifacts/example_mods/NPCArmor_Lite/gl_npcarmor_lite.ssl

@@ -11,7 +11,7 @@
 
    Requires sfall 3.8.29 or higher
 
-   version 1.1
+   version 1.4
 
 */
 
@@ -79,13 +79,13 @@ procedure check_weapon_change(variable critter, variable weapon, variable isWiel
 end
 
 /*
-   Finds the first weapon which can be used by the party member in the inventory
+   Finds the first weapon that can be used by the party member in the inventory
 */
 procedure search_alt_weapon(variable critter) begin
    variable obj, res, i := 0;
    obj := inven_ptr(critter, 0);
    while (obj) do begin
-      if (obj_item_subtype(obj) == item_type_weapon) then begin
+      if (obj_item_subtype(obj) == item_type_weapon and weapon_is_unusable(obj) == false) then begin
          if (unWieldWeapon == 0 or unWieldWeapon != obj_pid(obj)) then begin
             res := check_weapon_change(critter, obj, 1);
             if (res == -1) then begin