blah
Merge branch 'multispin-coding'
Move SA to new API

I’ve changed the SA routines so they use progcycles in the same way as
we have for the DWave_API package. Now, the two are almost identical
except for the truly fundamental differences between them (have to pass
url,name to define the solver for each progcycle for DW, and DW also
needs a token which we don’t want to save in the data as that would
violate security; SA you pass β_init and β_final).

Also export the function prodzip, which is crucial for the purpose of
generating said progcycles in a reasonable way. Now it’s basically a
single command.

Also moved get_energy to return a type that’s the same type as the
ProblemInstance, cutting down on conversions.

Added GaugeEmbedding(N) to trivially generate the identity embedding.