remove progressbar from correlation.py: Counter no longer exists
remove progressbar from correlation.py: Counter no longer exists

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