BUG: Possible fix for int_argsort in graph_utils. (#660)
BUG: Possible fix for int_argsort in graph_utils. (#660)

* faster rcm

* update norms

* Remove rcm bucky test

the use of int_argsort makes the exact perm array platform dependent.

* Switch to using vector in int_argsort

Hopefully this addresses some issues on OSX

qutip/qutip,qutip/qutip,cgranade/qutip,cgranade/qutip