update readme, adjust badge order

Author: oldratlee

README.md

@@ -1,8 +1,8 @@
 Java Dns Cache Manipulator(DCM)
 =========================
 
-[![Build Status](https://travis-ci.org/alibaba/java-dns-cache-manipulator.svg?branch=master)](https://travis-ci.org/alibaba/java-dns-cache-manipulator) [![Coverage Status](https://coveralls.io/repos/alibaba/java-dns-cache-manipulator/badge.svg?branch=master)](https://coveralls.io/r/alibaba/java-dns-cache-manipulator?branch=master) 
-[![GitHub issues](https://img.shields.io/github/issues/alibaba/java-dns-cache-manipulator.svg)](https://github.com/alibaba/java-dns-cache-manipulator/issues) [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.alibaba/dns-cache-manipulator/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.alibaba/dns-cache-manipulator/) [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0.html)
+[![Build Status](https://travis-ci.org/alibaba/java-dns-cache-manipulator.svg?branch=master)](https://travis-ci.org/alibaba/java-dns-cache-manipulator) [![Coverage Status](https://coveralls.io/repos/alibaba/java-dns-cache-manipulator/badge.svg?branch=master)](https://coveralls.io/r/alibaba/java-dns-cache-manipulator?branch=master) [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.alibaba/dns-cache-manipulator/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.alibaba/dns-cache-manipulator/) 
+[![GitHub issues](https://img.shields.io/github/issues/alibaba/java-dns-cache-manipulator.svg)](https://github.com/alibaba/java-dns-cache-manipulator/issues) [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0.html)
 
 :point_right: 通过代码直接设置`Java`的`DNS`（实际上设置的是`DNS Cache`），支持`JDK 6+`。
 
@@ -133,7 +133,8 @@ private static void cacheAddresses(String hostname,
 
 [`InetAddressCacheUtil`](src/main/java/com/alibaba/dcm/internal/InetAddressCacheUtil.java)类中对`DNS Cache`的读写也一致地加了以`addressCache`为锁的`synchronized`块，以保证线程安全。
 
-### 相关资料
+:books: 相关资料
+=====================================
 
 - [tanhaichao](https://github.com/tanhaichao)的[`javahost`项目](https://github.com/tanhaichao/javahost)，
     该项目的[使用文档](http://leopard.io/modules/javahost)。