Updates to mvp-sample application

Petter, I'm back again with some more updates.  I think this update really completes the `mvp-sample` by having the selection of a market day and participant result in something a little more gratifying than "No results". You now get a `TreeTable` of results.  There's probably other areas of investigation to write about in the `README`, and I may return w/ more on how navigation is powered as well as some of the additional utility code for pivoting hour data.