The calibration modal was not starting properly, because
the component was not mounted when its show method
was called. Calling it from the `mounted` method solves
the problem and we don't get the error.
I'm not 100% sure this was introduced by refactoring the
taskSubmitter, though it's possible. However, I think the
fix is uncontroversial and it should probably have been there
all along.
I've changed tasksubmitter to accept a "thing" and "action" rather than a single URL. This seems more in keeping with
propertyControl, and eliminates the need for loads of
computed properties.
I've also deleted (rather than just commenting out) chunks of the web app that are no longer in use. These may be
reinstated in the future - but we can get them from git
history. It's less confusing not to have vestigial
code in the repo.
This builds OK but is not, as yet, tested with hardware.
