Kotlin support

As more and more code in our app is being migrated to Kotlin we'd like to use Frodo there as well. However it seem that Kotlin isn't supported as of now.

However when using the Frodo annotations exclusively in Kotlin code we receive
```
advice defined in com.fernandocejas.frodo.aspect.LogSubscriber has not been applied [Xlint:adviceDidNotMatch]
advice defined in com.fernandocejas.frodo.aspect.LogSubscriber has not been applied [Xlint:adviceDidNotMatch]
```

This error doesn't appear and the Java code logging works, but in both cases logging for Kotlin classes doesn't work.

Hugo is suffering the same problem: https://github.com/JakeWharton/hugo/issues/121