Fixed the test_count_spins() unit test.
Removed the call to count_selected_spins().
Merged the count_selected_spins() function into count_spins().
Wrote the count_molecules() and count_residues() functions.
Wrote the determine_seq_type() function.
Fatal indentation fix.
Shifted the focus of the Grace module from residues to spins.
Fixed the calls to x_return_value() and y_return_value().
Fixed the call to get_data().
Removed a remaining instance of 'self' from the write() function.