Catkinized groovy devel

Catknizes the groovy-devel branch in a new branch called "groovy-devel-catkinized". Most of the work was already done by user @contradict ; I just pulled from his fork, fixed a few things to get it to compile, and rebased to include recent commits from the groovy-devel branch.

As I mentioned in #24, we probably shouldn't release from this branch, but it will be useful for people on groovy who would like a catkinized nav stack and don't mind working from source.