added dungeon to narnardinath's lair

water elemental / air elemental stats slightly tweaked, water elementals no longer have acid immunity / do acid damage

drown pulse attack added (and only does dmg, no instakill)

closes #832

Author: b5635

seeded_database/areadistances.txt

@@ -24923,6 +24923,10 @@
       }
     ]
   },
+  "TileBrdrDisabled": {
+    "type": "byte",
+    "value": 0
+  },
   "Tileset": {
     "type": "resref",
     "value": "trs02"