wet towel enhancements

Flesh out wet towels a bit:
1) wielding a wet towel--or a dry one which becomes wet--won't give a
   "you begin bashing with your wet towel" message when attacking;
2) if a formerly wet towel dries out completely while wielded, *do* give
   "you begin bashing with your towel" on the next attack;
3) successfully hitting with a wet towel no longer always loses wetness;
4) water damage to dry towel always confers at least 1 point of wetness;
5) taking fire damage (via burnarmor() which is used for most types of
   fire damage) has a chance to partially or fully dry a wet towel
   (regardless of whether it's wielded at the time; applies to monsters
   as well as hero; each towel being carried is checked until one is
   affected, then any others escape drying.

Not done:
-) attacking with a wielded wet towel perhaps ought to be treated as a
   weapon attack using whip skill rather than an augmented arbitrary-
   junk-by-weight attack;
-) throwing a wet towel should probably ignore wetness--it's just a wet
   piece of cloth when not finishing with a whip snap; right now, it
   loses a point of wetness when thrown and usually--#3 above--another
   point if it hits...;
-) hitting burning creatures is no different than hitting anything else;
-) likewise for hitting wet creatures.

include/obj.h

@@ -1,4 +1,4 @@
-/* NetHack 3.6	obj.h	$NHDT-Date: 1432512782 2015/05/25 00:13:02 $  $NHDT-Branch: master $:$NHDT-Revision: 1.49 $ */
+/* NetHack 3.6	obj.h	$NHDT-Date: 1445126423 2015/10/18 00:00:23 $  $NHDT-Branch: master $:$NHDT-Revision: 1.50 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -187,6 +187,9 @@ struct obj {
      && objects[otmp->otyp].oc_skill <= -P_DART)
 #define is_weptool(o) \
     ((o)->oclass == TOOL_CLASS && objects[(o)->otyp].oc_skill != P_NONE)
+        /* towel is not a weptool:  spe isn't an enchantment, cursed towel
+           doesn't weld to hand, and twoweapon won't work with one */
+#define is_wet_towel(o) ((o)->otyp == TOWEL && (o)->spe > 0)
 #define bimanual(otmp)                                            \
     ((otmp->oclass == WEAPON_CLASS || otmp->oclass == TOOL_CLASS) \
      && objects[otmp->otyp].oc_bimanual)