Do we need `base_unit`? about measured HOT 4 CLOSED

We can look at removing it. It's there to allow resolution of the conversion tree. But we may be able to define an arbitrary base, rather than giving one explicitly.

from measured.

If that's all it's for, I'd love to drop it and simply use a graph traversal algorithm to resolve the conversion tree between every pair of units. Adds some extra work to a hidden portion of the library but simplifies our public interface.

from measured.

You can take a stab at it. Part of the complexity of this is that we want the shortest, and want to avoid any lossy conversions. So going m -> cm -> mm doesn't matter because you collapse them down to a single conversion factor. But if you end up m -> in -> mm you introduce lossyness by including an imperfect conversion factor when it is not necessary.

from measured.

I decided that we should perhaps stick with a base unit, because a lot of standards arounds units of measure define a measurement system as a base unit and derived units. Given we've said conversions are done via UCUM, it makes sense to stick to that.

from measured.