Signature sorting options

[calintat]

We could have a button to choose which way to sort the signature: by name, by dimension, manually.

[jamievicary]

Maybe this would make more sense as actions, e.g. "Sort by name", "Sort by dimension". (Or maybe just "Sort", which would sort it principally by dimension, and alphabetically within that.) These actions would sort the list and destroy the previous sort.

[calintat]

Yes, that sounds better.