12-direction LOCGRAD and fully functional EPR

Yilmaz turned out to be a dud paper, now everything is based on
Prausnitz. LOCGRAD does single component transfers as well as
bi-directional trades now, and also now just eliminates moves that
would go off the edge instead of going closer and closer. Was able to
reproduce Prausnitz Fig. 1b including one metastable point.