Update ParityGroups to work with ZXXZ stabilizer protocol

[MiniSean]

So far, each ParityGroup has a fixed stabilizer type (X or Z) which determines the evaluation basis of all data qubits within that group.
Now, for the ZXXZ surface code protocol, we should have the ability to define a single ParityGroup with data qubits that are evaluated at different X or Z basis.
This issue introduces this concept per data qubit within the ParityGroup and removes the common StabilizerType from the ParityGroup.