new operator functions: spin_Jx, spin_Jy, spin_Jz etc, that provides a nicer API to access the jmat function. Made helper functions jplus and lz internal.
new operator functions: spin_Jx, spin_Jy, spin_Jz etc, that provides a nicer API to access the jmat function. Made helper functions jplus and lz internal.

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