Allow structs to be parsed in JSON with out of order fields.

Also simplified the code and made it faster.

Change-Id: I1d83b1165a4a9a4380d1bfb5538769c012d2d367
Tested: on Linux.

tests/MyGame/Example/Monster.cs

@@ -5,6 +5,7 @@ namespace MyGame.Example
 
 using FlatBuffers;
 
+/// an example documentation comment: monster object
 public sealed class Monster : Table {
   public static Monster GetRootAsMonster(ByteBuffer _bb) { return GetRootAsMonster(_bb, new Monster()); }
   public static Monster GetRootAsMonster(ByteBuffer _bb, Monster obj) { return (obj.__init(_bb.GetInt(_bb.Position) + _bb.Position, _bb)); }

tests/MyGame/Example/Monster.go

@@ -5,6 +5,7 @@ package Example
 import (
 	flatbuffers "github.com/google/flatbuffers/go"
 )
+/// an example documentation comment: monster object
 type Monster struct {
 	_tab flatbuffers.Table
 }

tests/MyGame/Example/Monster.java

@@ -8,6 +8,9 @@ import java.util.*;
 import com.google.flatbuffers.*;
 
 @SuppressWarnings("unused")
+/**
+ * an example documentation comment: monster object
+ */
 public final class Monster extends Table {
   public static Monster getRootAsMonster(ByteBuffer _bb) { return getRootAsMonster(_bb, new Monster()); }
   public static Monster getRootAsMonster(ByteBuffer _bb, Monster obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__init(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }

tests/MyGame/Example/Monster.py

@@ -4,6 +4,7 @@
 
 import flatbuffers
 
+# /// an example documentation comment: monster object
 class Monster(object):
     __slots__ = ['_tab']