Duplicate files copied (Android Studio 0.4.0) [duplicate]

Follow the advice Gradle gives you at the end of the build. In my case it told me to add:

android {
    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
    }
    // ...
}