Other golo commands as gradle tasks

[yloiseau]

Beside compile and run, which are already covered by tasks, the golo command line provides check that checks code for errors without creating the bytecode, and doc that create an API doc similar to javadoc.
It would be nice if the gradle plugin could provide tasks for these two behaviors.

[erdi]

I've written this plugin as an exercise to understand Gradle better and learn how one would add support for a new language in the form of a plugin. I'm not using this plugin myself and I'm also not aware of anybody else using it.

I'm happy to provide support if you wanted to work on a PR for this feature request but please be aware that I do not plan to work on it myself.