removed unnecessary 3D matplotlib imports from mechanical cooling example and set temp. range lower bound to 1mK from 0 to prevent overflow warnings
removed unnecessary 3D matplotlib imports from mechanical cooling example and set temp. range lower bound to 1mK from 0 to prevent overflow warnings

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