ENH Make relaxed inference a kwarg,

 so we can set it via the new dict interface. This makes it possible to choose between overgenerating inference and undergenerating inference (via rounding) for lp and ad3.

the kwarg thing is not so pretty but working around it is also not so nice...
The problem is that ``relaxed`` is set to ``True`` for loss-augmented inference in the learning code.
So all inference procedures will get it :-/