fix the singleton style and update the android studio to 2.1.0 preview 1

Author: fengjian

README.md

@@ -1,6 +1,6 @@
 # LessCode [![Jcenter Status](https://api.bintray.com/packages/openproject/maven/lesscode/images/download.svg)](https://bintray.com/openproject/maven/lesscode)
 
-less code, more efficient for android
+less code, more efficient for android, for the best android tools library!
 
 ## Overview
 

build.gradle

@@ -5,7 +5,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.0.0-beta6'
+        classpath 'com.android.tools.build:gradle:2.1.0-alpha1'
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.0'
         classpath 'com.github.dcendents:android-maven-gradle-plugin:1.3'
         // NOTE: Do not place your application dependencies here; they belong

lesscode-core/src/main/java/com/jayfeng/lesscode/core/$.java

@@ -6,7 +6,7 @@ public final class $ {
     /**
      * 单例
      */
-    private static $ instance;
+    private volatile static $ instance;
     public static $ getInstance() {
         if (instance == null) {
             synchronized ($.class) {