Added 'water.py' solvent component
Added 'water.py' solvent component

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