Stream features now use stanza objects!
Features are given a ranking that expresses the dependency
relationships (since only one feature is negotiated at a time, the
dependency graph can be replaced by a line).
>>> xmpp.register_feature('my_feature', _my_handler,
>>> restart=True, # Requires stream restart
>>> order=600) # Ranking (out of ~ 10,000,
>>> # lower #'s executed first)
SASL mechanisms may now be added or disabled as needed. Each mechanism
is given a priority value indicating the order in which the client
wishes for mechanisms to be tried. Higher priority numbers are executed
first.
>>> xmpp.register_sasl_mechanism('SASL-MECH', _mech_handler,
>>> priority=0)
Disabling a SASL mechanism:
>>> xmpp.remove_sasl_mechanism('ANONYMOUS')
