Add test for relational SEM spec of a BG ACE model.
Add test for relational SEM spec of a BG ACE model.

mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx