Set map.json files with map_obj_gfx constants

data/maps/LavenderTown_VolunteerPokemonHouse/map.json

@@ -14,7 +14,7 @@
   "connections": null,
   "object_events": [
     {
-      "graphics_id": "78",
+      "graphics_id": "MAP_OBJ_GFX_OLD_MAN_3",
       "x": 3,
       "y": 3,
       "elevation": 3,
@@ -27,7 +27,7 @@
       "flag": "53"
     },
     {
-      "graphics_id": "124",
+      "graphics_id": "MAP_OBJ_GFX_NIDORINO",
       "x": 1,
       "y": 4,
       "elevation": 3,
@@ -40,7 +40,7 @@
       "flag": "0"
     },
     {
-      "graphics_id": "121",
+      "graphics_id": "MAP_OBJ_GFX_PSYDUCK",
       "x": 9,
       "y": 6,
       "elevation": 3,
@@ -53,7 +53,7 @@
       "flag": "0"
     },
     {
-      "graphics_id": "16",
+      "graphics_id": "MAP_OBJ_GFX_LITTLE_BOY",
       "x": 9,
       "y": 5,
       "elevation": 3,
@@ -66,7 +66,7 @@
       "flag": "0"
     },
     {
-      "graphics_id": "18",
+      "graphics_id": "MAP_OBJ_GFX_YOUNGSTER",
       "x": 3,
       "y": 5,
       "elevation": 3,
@@ -79,7 +79,7 @@
       "flag": "0"
     },
     {
-      "graphics_id": "17",
+      "graphics_id": "MAP_OBJ_GFX_LITTLE_GIRL",
       "x": 7,
       "y": 2,
       "elevation": 3,