`CoilSet` "Family" akin to `EquilibriaFamily`

[ddudt]

trafficstars

I/O wrapper for a list of coil sets. Could be useful for keeping track of coil sets that correspond to equilibria within a family.

[f0uriest]

Might be more useful as a general IOAble family for arbitrary things, not just coils. And could make EquilibriaFamily a subclass

[dpanici]

define a save function in desc.io and allow saving of lists of IOAble objects

[ddudt]

I would also be in favor of removing the EquilibriaFamily class, since it has no unique functionality other than solve_continuation. Even then I think solve_continuation_automatic is more commonly used and in that case the user typically doesn't care about the intermediate solutions.

[dpanici]

I'd be in favor of that as well

[f0uriest]

I don't think we should get rid of it, since that would likely break every existing saved EquilibriaFamily