ValueFactory.MapBuilder is preferred to dpreserve value order

ImmutableMapValueImpl preserves order of values. This is preferred
behavior because it's preffered if created map objects preserve order of
values when an application forwards a received (or deserialized) objects
into another application without modifying it. This pull-request applies
this preference to MapBuilder.

Performance impact should be small because MapBuilder API is a minor
API.

Author: frsyuki

msgpack-core/src/main/java/org/msgpack/value/ValueFactory.java

@@ -29,7 +29,7 @@
 import java.math.BigInteger;
 import java.util.AbstractMap;
 import java.util.Arrays;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -191,10 +191,8 @@ public static ImmutableArrayValue emptyArray()
     ImmutableMapValue newMap(Map<K, V> map)
     {
         Value[] kvs = new Value[map.size() * 2];
-        Iterator<Map.Entry<K, V>> ite = map.entrySet().iterator();
         int index = 0;
-        while (ite.hasNext()) {
-            Map.Entry<K, V> pair = ite.next();
+        for (Map.Entry<K, V> pair : map.entrySet()) {
             kvs[index] = pair.getKey();
             index++;
             kvs[index] = pair.getValue();
@@ -252,7 +250,7 @@ public static Map.Entry<Value, Value> newMapEntry(Value key, Value value)
 
     public static class MapBuilder
     {
-        private final Map<Value, Value> map = new HashMap<Value, Value>();
+        private final Map<Value, Value> map = new LinkedHashMap<Value, Value>();
 
         public MapBuilder() {}