TODO: Check compatibility with Mplus output

[marklhc]

The semPaths() function can work with Mplus output (see here), although it's not clear to me whether it can extract parameter estimates. So it should work with the following functions that do not depend on a lavaan fit object:

• rotate_resid()
• set_curve()
• set_edge_label_position()
• set_cfa_layout()
• set_sem_layout()

This is not urgent as the priority should be to make the functions work without bugs for lavaan.