allow config init size of jsonarray and jsonobject (#81)

Author: hezhangjian

json-smart/src/main/java/net/minidev/json/JSONArray.java

@@ -30,6 +30,13 @@
 public class JSONArray extends ArrayList<Object> implements List<Object>, JSONAwareEx, JSONStreamAwareEx {
 	private static final long serialVersionUID = 9106884089231309568L;
 
+	public JSONArray() {
+	}
+
+	public JSONArray(int initialCapacity) {
+		super(initialCapacity);
+	}
+
 	public static String toJSONString(List<? extends Object> list) {
 		return toJSONString(list, JSONValue.COMPRESSION);
 	}

json-smart/src/main/java/net/minidev/json/JSONObject.java

@@ -35,6 +35,10 @@ public JSONObject() {
 		super();
 	}
 
+	public JSONObject(int initialCapacity) {
+		super(initialCapacity);
+	}
+
 	/**
 	 * Escape quotes, \, /, \r, \n, \b, \f, \t and other control characters
 	 * (U+0000 through U+001F). It's the same as JSONValue.escape() only for