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.

Start with the Gradle configuration shown in the issue and read the two linked comments for the expected Android behavior. Reproduce the setup with and without target "src/*/java/**/*.java"; done means Android Java sources are handled without requiring that target configuration.

Written by the indexing model from the issue text.