build.gradle (project)

buildscript {
    repositories {
        maven { url 'http://repo1.maven.org/maven2' }
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.0'
    }
}

repositories {
    maven { url 'http://repo1.maven.org/maven2' }
}

allprojects {
    repositories {
        maven { url 'http://repo1.maven.org/maven2' }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}