Automatic Android support without specifying target "src/*/java/**/*.java"

Does this support Android?

---
EDIT BY @nedtwigg, TOP COMMENT FOR VISIBILITY

On Android, your config file needs to look like this:

```gradle
spotless {
java {
target "src/*/java/**/*.java" // this line is needed
}
}
```

We'd love a PR which fixes this, see [this comment](https://github.com/diffplug/spotless/issues/111#issuecomment-301555611) and [this comment](https://github.com/diffplug/spotless/issues/111#issuecomment-301673111) for what needs to be done.