jobs that were created outside the database.  Also added ability to not
write (doesn't execute write_output or dataflow jobs).  Improved logic so
that if a job is specified, but something is wrong that the worker fails
rather than reverting to autonomous behaviour mode.

runWorker.pl now provides much better debugging capability through the
use of the -logic_name, -input_id and -no_write combination.

Fully tested by running a complete homology production test.