Added link to jobs page to fix any issues caused by non-synchronised
time between webserver/worker machine leaving jobs permanently in the
running state.
Prevented the insertion of new status records unless the state is
actually being changed.
Made the HandBrake worker process write the status complete message
instead of the run-jobs dispatched, in case it crashes.
The Perl version of gearman doesn't support passing the unique value to
the worker, so the job id is now passed in the workload request.
Also fixed a bug to ensure changes to job status are visible
immediately, rather than only on the next page load.
