Update lumbermill map+dialogue

-Outer fence is no longer permalocked with no way in
-You can ask for a gate to be opened.

data/json/mapgen/occupied_lumber_mill/occupied_lumber_mill.json

@@ -45,7 +45,7 @@
         "v        2    _________________________________;",
         "v vvvvv    *___________________________1 1  ___;",
         "v vooov______________________   ____ 121   1  _#",
-        "v voGoV_____________ #.......#. ____ 1 1*1 1 1 v",
+        "v voGoX_____________ #.......#. ____ 1 1*1 1 1 v",
         "v vooov_________     #L.....L#* ____*  1 1 1 2 v",
         "v vvvvv   ______  * *wL.....Lw   ____1 1 1 1  *v",
         "v         1____ 2    #L.....L# * ____1 1*  1   v",
@@ -103,6 +103,15 @@
       ]
     }
   },
+  {
+    "type": "mapgen",
+    "update_mapgen_id": "ocu_lumbermill_opens_a_gate",
+    "method": "json",
+    "object": {
+      "flags": [ "ERASE_ALL_BEFORE_PLACING_TERRAIN" ],
+      "set": [ { "square": "terrain", "id": "t_thconc_floor", "x": 10, "y": 23, "x2": 13, "y2": 23 } ]
+    }
+  },
   {
     "type": "mapgen",
     "method": "json",

data/json/mapgen_palettes/lumberyard.json

@@ -11,7 +11,8 @@
       "2": "t_stump",
       "o": "t_concrete",
       "v": "t_chainfence",
-      "V": "t_chaingate_l",
+      "V": "t_chaingate_c",
+      "X": "t_chaingate_l",
       "w": "t_window",
       ";": "t_door_metal_locked",
       "6": "t_gates_mech_control_lab",

data/json/npcs/lumbermill_employees/TALK_lumbermill_merchant.json

@@ -41,6 +41,10 @@
         "condition": { "compare_string": [ "yes", { "npc_val": "dialogue_first_meeting_talked_to_merchant" } ] }
       },
       { "text": "Can I purchase some of your wares?", "topic": "TALK_LUMBERMILL_FABRICATE" },
+      {
+        "text": "Can I use the gate?  I'd like to bring a vehicle for trade.",
+        "topic": "TALK_LUMBERMILL_GATE_PERMISSION"
+      },
       {
         "text": "Any jobs you need done?",
         "condition": { "and": [ { "not": "has_assigned_mission" }, { "not": "has_many_assigned_missions" } ] },
@@ -49,6 +53,18 @@
       { "text": "<end_talking_leave>", "topic": "TALK_DONE" }
     ]
   },
+  {
+    "type": "talk_topic",
+    "id": "TALK_LUMBERMILL_GATE_PERMISSION",
+    "dynamic_line": "I'll tell the guys to open one of the gates, but you gotta promise to be careful.  We've got a simple rule here: You break it, you buy it!",
+    "responses": [
+      {
+        "text": "I'll be careful.",
+        "effect": { "mapgen_update": "ocu_lumbermill_opens_a_gate", "om_terrain": "lumbermill_1_1_ocu" },
+        "topic": "TALK_NPC_LUMBERMILL_MERCHANT_INTRO"
+      }
+    ]
+  },
   {
     "type": "talk_topic",
     "id": "TALK_NPC_LUMBERMILL_MERCHANT_STORY",