Experiment with a Lensy API

[joe-warren]

There are a bunch of functions in Waterfall CAD which could be implemented as optics.

Being linear transforms, all of the functions in Waterfall.Transforms could be implemented as isomorphisms.

You could also write Lenses that use one Solid to "mask off" part of another (such that solidA ^. (mask solidB) == solidA `intersection` solidB).

I've tried to keep simplicity in mind in the design of the Waterfall API, so I'm not sure I'm keen to add Optics to itl; but I do think it'd be worth exploring this space.