This involves a number of changes. The pseudo-atom specific functions ave_rdc_tensor_pseudoatom()
and ave_rdc_tensor_pseudoatom_dDij_dAmn() have been added to the lib.alignment.rdc module. These
simply average the values from the equivalent non-pseudo-atom functions. The return_rdc_data()
function in the specific_analyses.n_state_model.data module has been modified to assemble the RDC
constants and unit vectors for all members of the pseudo-atom and add these to the returned
structures, as well as a new list of flags specifying if the interatom pair contains pseudo-atoms.
The N-state model target function and gradient have been updated to send the pseudo-atom data to the
new lib.alignment.rdc module functions.
