fix invalid json format.

* string must be written with double quotes.
* remove commma after the last object member.

tests/monsterdata_test.json

@@ -1,78 +1,78 @@
 {
-  pos: {
-    x: 1,
-    y: "2",
-    z: 3,
-    test1: 3,
-    test2: Green,
-    test3: {
-      a: 5,
-      b: 6
+  "pos": {
+    "x": 1,
+    "y": "2",
+    "z": 3,
+    "test1": 3,
+    "test2": "Green",
+    "test3": {
+      "a": 5,
+      "b": 6
     }
   },
-  hp: 80,
-  name: "MyMonster",
-  inventory: [
+  "hp": 80,
+  "name": "MyMonster",
+  "inventory": [
     0,
     1,
     2,
     3,
     4
   ],
-  vector_of_longs: [
+  "vector_of_longs": [
       1,
       100,
       10000,
       1000000,
       100000000
   ],
-  vector_of_doubles: [
+  "vector_of_doubles": [
       -1.7976931348623157e+308,
       0,
       1.7976931348623157e+308
   ],
-  test_type: Monster,
-  test: {
-    name: "Fred",
-    pos: null
+  "test_type": "Monster",
+  "test": {
+    "name": "Fred",
+    "pos": null
   },
-  test4: [
+  "test4": [
     {
-      a: 10,
-      b: 20
+      "a": 10,
+      "b": 20
     },
     {
-      b: "40",
-      a: 30
+      "b": "40",
+      "a": 30
     }
   ],
-  test5: [
+  "test5": [
     {
-      a: 10,
-      b: 20
+      "a": 10,
+      "b": 20
     },
     {
-      b: "40",
-      a: 30
+      "b": "40",
+      "a": 30
     }
   ],
-  testarrayofstring: [
+  "testarrayofstring": [
     "test1",
     "test2"
   ],
-  enemy: {
-    name: "Fred"
+  "enemy": {
+    "name": "Fred"
   },
-  testarrayofbools:[
+  "testarrayofbools":[
     true, false, true
   ],
-  testbool: true,
-  testhashs32_fnv1: "This string is being hashed!",
-  testhashu32_fnv1: "This string is being hashed!",
-  testhashs64_fnv1: "This string is being hashed!",
-  testhashu64_fnv1: "This string is being hashed!",
-  testhashs32_fnv1a: "This string is being hashed!",
-  testhashu32_fnv1a: "This string is being hashed!",
-  testhashs64_fnv1a: "This string is being hashed!",
-  testhashu64_fnv1a: "This string is being hashed!",
+  "testbool": true,
+  "testhashs32_fnv1": "This string is being hashed!",
+  "testhashu32_fnv1": "This string is being hashed!",
+  "testhashs64_fnv1": "This string is being hashed!",
+  "testhashu64_fnv1": "This string is being hashed!",
+  "testhashs32_fnv1a": "This string is being hashed!",
+  "testhashu32_fnv1a": "This string is being hashed!",
+  "testhashs64_fnv1a": "This string is being hashed!",
+  "testhashu64_fnv1a": "This string is being hashed!"
 }