Hey guys,

Just a heads-up, I am working on folder support. Here is a snapshot of what I have so far:
213bb62

If you have any advice/feedback about how you'd like it done, feel free to chime in, but don't feel like you need to waste any time on it necessarily until I'm done. I've examined the code pretty carefully and I think I am making decisions similar to the structure of other things fairly consistently, so hopefully it will be an easy PR to take.

My basic approach so far is adding a FolderJob object, and JenkinsServer.getFolder(Job someJob) which returns a FolderJob object (regardless of job type), on which you can call isFolder() to see if it is a valid folder. Then, on the FolderJob, you can call getJobs() to get the jobs under it.

I'll also add JenkinsServer.createFolder() and FolderJob.createFolder(), which will probably throw an error if you don't have the cloudbees plugin installed.

The linked history also includes some bugfixes and refactorings.