Finish Core implementation of Auto-Web API

* Converted bash tests to a basic python test harness/system diagnostic
* Various fixes inside the arduino test host to match how things should work
* Added support for functions with arguments
* Added support for handling responses which are actually results
* Added tests for all the common usecases
* Return values from Web API changed to be a bit more consistent with the target
  spec to allow better introspection to allow automated tests.

NB, while the functionality is largely in place, it doesn't yet conform to the
original intended spec, and still needs a bit of work around consistency and
uniformity. This is a major milestone despite that.
Update status, sync'd with Trello