Revert "Three schemes for parallelizing GREML derivatives."
Revert "Three schemes for parallelizing GREML derivatives."

This reverts commit fa2b873e1bcfe17c9a228b5aa2f317e0dff94e24.

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