Updated the bundle to support prefixes for jobs/tasks. This adds support for using a single gearmand server but have different environments for dev and prod.

Now you can optionally specify a job_prefix under the default settings. By default this will be null and have no affect on anything.
If you specify one such as 'dev' it will prepend all tasks and job.  This will require zero updates between live and dev environments of your code.
Also updated the describer and list commands to show the prefix is there is one in use.