Allow viewing and manipulating the queue for jobs
Make jobqueue column name consistent

It was spelled job_queue in some places and jobqueue in others.  Now
it's jobqueue everywhere.
Avoid sending multiple notifications on job done
Fix wrong data type in docstring
Import and use _WorkState for comparisons
Reduce the height of job columns

This reduces the height of job columns by making the progress bar inline
with the task counts and removing its 20 pixel bottom margin.
Merge pull request #264 from guidow/height_reduce_job_rows

Reduce the height of job columns
Merge pull request #260 from guidow/queue_in_job_api

Allow viewing and manipulating the queue for jobs
Merge pull request #263 from guidow/no_multi_done_mails

Avoid sending multiple notifications on job done