Use `OptChain` as an alias for `OptimiserChain`?

[CarloLucibello]

OptimiserChain is a bit too verbose, with OptChain we go from 14 to 8 characters without losing clarity.

[mcabbott]

I had a branch somewhere to change the printing to ClipNorm(1) => Descent(0.1), and also digest such strings of =>. 2 characters and no brackets.

Pushed as #139 now

[CarloLucibello]

Let's keep OptimiserChain as it is consolidated