Set map.json files with map_obj_gfx constants

data/maps/SevenIsland_TrainerTower_6F/map.json

@@ -14,7 +14,7 @@
   "connections": null,
   "object_events": [
     {
-      "graphics_id": "70",
+      "graphics_id": "MAP_OBJ_GFX_TRAINER_TOWER_DUDE",
       "x": 9,
       "y": 7,
       "elevation": 3,
@@ -27,7 +27,7 @@
       "flag": "6"
     },
     {
-      "graphics_id": "240",
+      "graphics_id": "MAP_OBJ_GFX_VAR_0",
       "x": 10,
       "y": 10,
       "elevation": 3,
@@ -40,7 +40,7 @@
       "flag": "2"
     },
     {
-      "graphics_id": "241",
+      "graphics_id": "MAP_OBJ_GFX_VAR_1",
       "x": 15,
       "y": 13,
       "elevation": 3,
@@ -53,7 +53,7 @@
       "flag": "3"
     },
     {
-      "graphics_id": "242",
+      "graphics_id": "MAP_OBJ_GFX_VAR_2",
       "x": 10,
       "y": 16,
       "elevation": 3,
@@ -66,7 +66,7 @@
       "flag": "4"
     },
     {
-      "graphics_id": "243",
+      "graphics_id": "MAP_OBJ_GFX_VAR_3",
       "x": 11,
       "y": 10,
       "elevation": 3,