Equivilent of Zygote.refresh: force recompiling of everthing

[oxinabox]

Zygote.refresh is needed to get Zygote to pickup new rrules, we don't need that.
but it would still be nice to have a way to force recompilation after we change something in the internals.
This would save needing to restart julia each time the internals are modified.

Since we don't want to hook back-edges from Diffractor's internals to every method it generates.
Though we could, I think it would be too error prone and annoying.

Came up in discussion with @nmheim