Allow mxComputeNothing() to obtain the default compute plan
Allow mxComputeNothing() to obtain the default compute plan

jpritikin/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,JuKa87/OpenMx,jpritikin/OpenMx,JuKa87/OpenMx,jpritikin/OpenMx,JuKa87/OpenMx,mhunter1/OpenMx,jpritikin/OpenMx,JuKa87/OpenMx,jpritikin/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,JuKa87/OpenMx,mhunter1/OpenMx,mhunter1/OpenMx,JuKa87/OpenMx