Support refining for tuples/sets of permutations, transformations, partial permutations

[wilfwilson]

(This is probably a more relevant issue for GraphBacktracking, we'll see).

We should be able to search for stabilisers and transporter sets of the following kinds of objects, with respect to the actions OnPoints, OnSets, and OnTuples:

• Permutations (already implemented for OnPoints in GB_Con.PermConjugacy)
• Transformations
• Partial Permutations

They should all pretty much be special cases of the OnDigraphs, OnTuplesDigraphs, OnSetsDigraphs refiners, I think.