added backwards compatible check and maps

maps/tests/function_tiles.json

@@ -0,0 +1,33 @@
+{ "columns":2,
+ "image":"function_tiles.png",
+ "imageheight":64,
+ "imagewidth":64,
+ "margin":0,
+ "name":"function_tiles",
+ "spacing":0,
+ "tilecount":4,
+ "tiledversion":"1.6.0",
+ "tileheight":32,
+ "tiles":[
+        {
+         "id":0,
+         "properties":[
+                {
+                 "name":"start",
+                 "type":"string",
+                 "value":"S1"
+                }]
+        }, 
+        {
+         "id":1,
+         "properties":[
+                {
+                 "name":"start",
+                 "type":"string",
+                 "value":"S2"
+                }]
+        }],
+ "tilewidth":32,
+ "type":"tileset",
+ "version":"1.6"
+}

maps/tests/start-tile.json

@@ -0,0 +1,95 @@
+{
+  "compressionlevel": -1,
+  "height": 5,
+  "infinite": false,
+  "layers": [
+    {
+      "data": [
+        4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+        4
+      ],
+      "height": 5,
+      "id": 4,
+      "name": "background",
+      "opacity": 1,
+      "type": "tilelayer",
+      "visible": true,
+      "width": 5,
+      "x": 0,
+      "y": 0
+    },
+    {
+      "data": [
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 3, 0, 0, 2, 3, 3, 0, 2,
+        2
+      ],
+      "height": 5,
+      "id": 1,
+      "name": "start",
+      "opacity": 1,
+      "type": "tilelayer",
+      "visible": true,
+      "width": 5,
+      "x": 0,
+      "y": 0
+    },
+    {
+      "draworder": "topdown",
+      "id": 3,
+      "name": "floorLayer",
+      "objects": [],
+      "opacity": 1,
+      "type": "objectgroup",
+      "visible": true,
+      "x": 0,
+      "y": 0
+    }
+  ],
+  "nextlayerid": 5,
+  "nextobjectid": 1,
+  "orientation": "orthogonal",
+  "renderorder": "right-down",
+  "tiledversion": "1.6.0",
+  "tileheight": 32,
+  "tilesets": [
+    {
+      "columns": 2,
+      "firstgid": 1,
+      "image": "function_tiles.png",
+      "imageheight": 64,
+      "imagewidth": 64,
+      "margin": 0,
+      "name": "function_tiles",
+      "spacing": 0,
+      "tilecount": 4,
+      "tileheight": 32,
+      "tiles": [
+        {
+          "id": 0,
+          "properties": [
+            {
+              "name": "start",
+              "type": "string",
+              "value": "S1"
+            }
+          ]
+        },
+        {
+          "id": 1,
+          "properties": [
+            {
+              "name": "start",
+              "type": "string",
+              "value": "S2"
+            }
+          ]
+        }
+      ],
+      "tilewidth": 32
+    }
+  ],
+  "tilewidth": 32,
+  "type": "map",
+  "version": "1.6",
+  "width": 5
+}