Add test for directional CRF
Add test for directional CRF

amueller/pystruct,pystruct/pystruct,d-mittal/pystruct,wattlebird/pystruct,wattlebird/pystruct,amueller/pystruct,d-mittal/pystruct,massmutual/pystruct,pystruct/pystruct,massmutual/pystruct