added unit tests for some gates and for gate expansion from 1,2,3 qubit spaces to N qubit spaces
added unit tests for some gates and for gate expansion from 1,2,3 qubit spaces to N qubit spaces

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