Setup Dagger 2 should explain bit more about annotation processing

[Goran1708]

https://github.com/codepath/android_guides/wiki/Dependency-Injection-with-Dagger-2

Setup part should mention after first paragraph that after gradle plugin 2.2.0 we should remove apply plugin: 'com.neenbedankt.android-apt' and use annotationProcessor or even better move that into https://github.com/codepath/android_guides/wiki/Getting-Started-with-Gradle and link that to dagger setup page.

Basically this https://stackoverflow.com/questions/37893533/android-studio-2-2-how-to-apply-dagger2-without-android-apt-plugin

[rogerhu]

Updated here:https://github.com/codepath/android_guides/wiki/Getting-Started-with-Gradle#upgrading-gradle