Remove old groovy stacks & update branch names

- Groovy: remove of 3 old (unmaintained) stacks, and replace with new one.
- Hydro & Indigo: Fix wrong branch name in Indigo; now we'll use the same upstream branch for both releases as long as it's possible. 
@tfoote : To be honest, the code hasn't been tested in Groovy, so perhaps it's better and simpler to just remove the old pkgs from the groovy repo list instead of replacing them with the newer ones. If you think that's OK I'll update the PR. 
Thanks in advance.