Connect the calculator wireframe up to the model

In !8 (merged) @mrognlie prepared the calculator wireframe. Based on @jdevine's review, we are now ready to connect this wireframe up to the model.

Since there are no sliders in the calculator, and we simply have a "Calculate" button, it should be relatively easy (the devil is in the detail!) to simply construct the model in a linear fashion, rather than using the dynamic state capability that the expert app is using.

One thing to note though - we shouldn't allow the calculator inputs to be changed whilst still displaying the calculated results from a previous state since this could easily be misunderstood.