Fixes #7. List of workers is now displayed in web UI.
Renamed Client::job() to ::getJob(), to adopt more bean-friendly naming, and to make room for upcoming ::getJobs() that performs multiget.
Fixes #7. API now provides access to worker stats, and worker jobs.
Fixes #8. API now provides access to qless.luq 'multiget' for bulk access to a worker's jobs.