Update readme file for swift3

Author: zhigang1992

README.md

@@ -1,25 +1,25 @@
 #SwiftyJSON
- 
+
 [![Travis CI](https://travis-ci.org/SwiftyJSON/SwiftyJSON.svg?branch=master)](https://travis-ci.org/SwiftyJSON/SwiftyJSON)
 
 SwiftyJSON makes it easy to deal with JSON data in Swift.
 
 1. [Why is the typical JSON handling in Swift NOT good](#why-is-the-typical-json-handling-in-swift-not-good)
-1. [Requirements](#requirements)
-1. [Integration](#integration)
-1. [Usage](#usage)
-	- [Initialization](#initialization)
-	- [Subscript](#subscript)
-	- [Loop](#loop)
-	- [Error](#error)
-	- [Optional getter](#optional-getter)
-	- [Non-optional getter](#non-optional-getter)
-	- [Setter](#setter)
-	- [Raw object](#raw-object)
-	- [Literal convertibles](#literal-convertibles)
-1. [Work with Alamofire](#work-with-alamofire)
-
-> For Swift3 support, take a look at the [swift3 beta branch](https://github.com/SwiftyJSON/SwiftyJSON/tree/swift3)
+2. [Requirements](#requirements)
+3. [Integration](#integration)
+4. [Usage](#usage)
+   - [Initialization](#initialization)
+   - [Subscript](#subscript)
+   - [Loop](#loop)
+   - [Error](#error)
+   - [Optional getter](#optional-getter)
+   - [Non-optional getter](#non-optional-getter)
+   - [Setter](#setter)
+   - [Raw object](#raw-object)
+   - [Literal convertibles](#literal-convertibles)
+5. [Work with Alamofire](#work-with-alamofire)
+
+> For Legacy Swift support, take a look at the [swift2 branch](https://github.com/SwiftyJSON/SwiftyJSON/tree/swift2)
 
 > [中文介绍](http://tangplin.github.io/swiftyjson/)
 
@@ -83,7 +83,7 @@ if let userName = json[999999]["wrong_key"]["wrong_name"].string {
 ## Requirements
 
 - iOS 7.0+ / OS X 10.9+
-- Xcode 7
+- Xcode 8
 
 ##Integration