Wrap all Jig run methods in an exception handler.

This makes error handling in delayed_jobs simpler and more robust by
making sure that all errors are trapped and reported in the runlog
without having to manually do it every time.
Merge pull request #70 from VictorLowther/robustify-jig-run-error-handling

+2 - thanks for pulling out some log noise.  Wrap all Jig run methods in an exception handler.