FLOE-171: Upgraded metadata demo with the new infusion model relay system

@amb26, can you review this pull request, our first pilot of the new model relay.
typeof checks are never required for undefined values unless these are global references. 
if (directModel.model === undefined) is sufficient here - 
however, this check seems suspicious and suggests that there is possibly some kind of race condition during initialisation? Why might the contents of "model" be undefined here?