corrected description of rho0 in docstrings
corrected description of rho0 in docstrings

anubhavvardhan/qutip,qutip/qutip,anubhavvardhan/qutip,qutip/qutip,cgranade/qutip,zasdfgbnm/qutip,cgranade/qutip,zasdfgbnm/qutip