Add groovy defaults

Lots of cleanup here.

- Fixes a bug where git repo is not searched upwards
- Add default config for Groovy projects
- Configure multi-project setup

To run check on all projects, you'd do this:

```
./gradlew check
```

To run it only on the root project:

```
./gradlew :check
```

- Fix up logging; it was being output twice instead of just once
- Setup local publishing of artifact for more consistent testing

```
./gradlew :publishLocal
./gradlew :stalk --info
```