Fix the default sorting for jobs

The UI would indicate a default sort by title when visiting the jobs
page.  This sort did not actually work, though, because sort was only
applied when an explicit order_by argument was given on the url.
Allow user to get task logs via UI
Clarify some error messages
Show some more information in job view
Merge pull request #224 from guidow/job_ui_more_info

Show some more information in job view
Merge pull request #223 from guidow/get_logfiles_ui

Allow user to get task logs via UI
Merge pull request #219 from guidow/fix_default_job_sort

Fix the default sorting for jobs