Gradle build script with API 21 min SDK to skip some dex overhead when developing against Lollipop and above.

gistfile1.txt

android {
  productFlavors {
    app {
    }

    appFast {
      // dev utilizes minSDKVersion = 21 to allow the Android gradle plugin
      // to pre-dex each module and produce an APK that can be tested on
      // Android Lollipop without time consuming dex merging processes.
      minSdkVersion 21
    }
  }

  sourceSets {
    appFast.setRoot('src/app')
  }
}