updated deepcopy logic of compound
updated deepcopy logic of compound

iModels/mbuild,sallai/mbuild,sallai/mbuild,tcmoore3/mbuild,ctk3b/mbuild,ctk3b/mbuild,tcmoore3/mbuild,summeraz/mbuild,summeraz/mbuild,Jonestj1/mbuild,Jonestj1/mbuild,iModels/mbuild