Make sure that subscribeToRosterSuggestions is ...

called sequentially with enough time between each call.
Bugfix. .roster-group elements must be found relative to
Keep on getting disconnected. This fixed it.

Seems like the RID gets incremented once too many (outside of upper bound of
expected window), and then server responds with item-not-found.

See: http://xmpp.org/extensions/xep-0124.html
Performance fix. Don't loop through whole roster when only one item changed. updates #151
Performance fix. Don't query for the roster on each page load.

Instead, just populate the roster from sessionStorage if available.
Keep a local customized copy of strophe.roster.js

The new changes made to strophe.roster.js are incompatible with the way
converse.js works.

Will likely replace strophe.roster.js completely.
Fix tests