Removed the empty molecule, residue, and spin modules.
Converted the number_residue() fn to the form of the number_spin() fn.
Big simplifications to the molecule and residue naming functions.
Shifted all the numbering functions into generic_fns.mol_res_spin.
Shifted all the naming functions into generic_fns.mol_res_spin.
Renamed all the 'rename' and 'renumber' fns to 'name' and 'number'.
Shifted all the display functions into generic_fns.mol_res_spin.
Shifted all the delete functions into generic_fns.mol_res_spin.
Shifted all the create functions into generic_fns.mol_res_spin.
Shifted all the copy functions into generic_fns.mol_res_spin.