Bump gradle plugin to 1.1.3

We also no longer depend on the undocumented internal variable sdkFolder

F-Droid/build.gradle

@@ -178,7 +178,21 @@ android.applicationVariants.all { variant ->
         title = "$name $version API"
         description "Generates Javadoc for F-Droid."
         source = variant.javaCompile.source
-        ext.androidJar = "${android.plugin.sdkFolder}/platforms/${android.compileSdkVersion}/android.jar"
+
+        def sdkDir
+        Properties properties = new Properties()
+        File localProps = project.rootProject.file('local.properties')
+        if (localProps.exists()) {
+            properties.load(localProps.newDataInputStream())
+            sdkDir = properties.getProperty('sdk.dir')
+        } else {
+            sdkDir = System.getenv('ANDROID_HOME')
+        }
+        if (!sdkDir) {
+            throw new ProjectConfigurationException("Cannot find android sdk. Make sure sdk.dir is defined in local.properties or the environment variable ANDROID_HOME is set.", null)
+        }
+
+        ext.androidJar = "${sdkDir}/platforms/${android.compileSdkVersion}/android.jar"
         classpath = files(variant.javaCompile.classpath.files) + files(ext.androidJar)
         options.links("http://docs.oracle.com/javase/7/docs/api/");
         options.links("http://d.android.com/reference/");

build.gradle

@@ -20,7 +20,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.0.1'
+        classpath 'com.android.tools.build:gradle:1.1.3'
 
         // libsuperuser submodule requires these plugins, even though
         // the F-Droid build process never invokes code from them. It