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.
{that}.options.source is where all arguments fired for createOnEvent - onCreateInput are saved. 

{that}.options.source.3 is to retrieve the last argument "isLastInstance".

Here's the calculation of "isLastInstance" and the arguments fired for onCreateInput event:
https://github.com/cindyli/metadata/blob/FLOE-171/src/js/resourceInputPanel.js#L346