classes.tuple: switch to python's tuplehash().  Fixes #153.
classes.tuple: switch to python's tuplehash().  Fixes #153.

erg/factor,mcandre/factor,erg/factor,mcandre/factor,erg/factor,mcandre/factor,erg/factor,mcandre/factor,mcandre/factor,mcandre/factor,erg/factor,erg/factor,erg/factor,mcandre/factor