Update compileSdkVersion and buildToolsVersion and Readme file

Author: tony-mak

README.md

@@ -1,15 +1,15 @@
 Test Device Policy Control (Test DPC) App
 =========================================
 
-Test DPC is an app designed to help EMMs, ISVs, and OEMs to test their applications and platforms in a Android for Work managed profile (i.e. work profile). It serves as both a sample Device Policy Controller and a testing application to flex the APIs available for Android for Work. It supports devices running Android 5.0 Lollipop or later. As of June 8, 2016, it also includes support for devices running API level 24.
+Test DPC is an app designed to help EMMs, ISVs, and OEMs to test their applications and platforms in a Android for Work managed profile (i.e. work profile). It serves as both a sample Device Policy Controller and a testing application to flex the APIs available for Android for Work. It supports devices running Android 5.0 Lollipop or later. As of Mar 24, 2017, it also includes support for devices running API level 26.
 
 See the [documentation](https://developer.android.com/work/index.html) to learn more about Android for Work.
 
 Pre-requisites
 --------------
 
-- Android N SDK
-- Android Build Tools v24.0.0
+- Android O preview SDK
+- Android Build Tools v26.0.0-rc1
 - Android Support Repository
 
 Getting Started

app/build.gradle

@@ -11,8 +11,8 @@ ext {
 }
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion "26.0.0"
+    compileSdkVersion 'android-O'
+    buildToolsVersion '26.0.0-rc1'
 
     defaultConfig {
         applicationId "com.afwsamples.testdpc"