Next up is just to clean those tests and replace the stupid
act_local_rotation2 with something legible.

Looks like nondeterminism in `next(d.iterkeys())` was breaking
consistency with A&B. Next up: switching determinism on or off.

Had a dumb translation error

Some tests are disabled and forcing outcomes does not work

Dunno why it was ever `complex`

Actually happened in previous commit, can't be bothered to amend

It's kinda ghastly at the moment. But lots of obvious improvements.

Added some more terms to clifford.by_name to ease lookup of complex
conjugates

Added GraphState.toggle_edges(), used by GraphState.measure_x

Nearly finished GraphState.measure_x