YASP (yet another semantics proposal)

Based on the call today, I've come up with a different proposal from
Bruce's semantics proposal that may or may not be the idea that Deyan was
thinking of. I wrote up something that mostly parallels what Bruce wrote
and copied most of the examples he had and marked them up with this new
proposal.

It is at: https://mathml-refresh.github.io/mathml/docs/function-semantics

Feedback is welcome. I'm sure there are plenty of typos and maybe some
things that aren't clear; hopefully it is understandable. We'll go over
this next week along with any other proposals people come up with.

   Neil