Upgrade SDK to 25

Upgrade compiledSDKVersion to 25, buildtools to 25.0.1, and
targetSDK to 25

Author: iankchristie

android/PhysicalWeb/app/build.gradle

@@ -4,7 +4,7 @@ apply plugin: 'pmd'
 
 android {
     compileSdkVersion 25
-    buildToolsVersion "25.0.0"
+    buildToolsVersion "25.0.1"
 
     defaultConfig {
         applicationId "physical_web.org.physicalweb"