added preliminary support for preconditioned CG
added preliminary support for preconditioned CG

cusplibrary/cusplibrary,cusplibrary/cusplibrary,cusplibrary/cusplibrary,sdalton1/cusplibrary,sdalton1/cusplibrary,sdalton1/cusplibrary,cusplibrary/cusplibrary,sdalton1/cusplibrary