Fix see-other-host handling if no host is actually given. Also, limit number of consecutive redirection attempts.

Resolved by always normalizing JIDs to bare form, regardless of if they
are JID objects or strings.

Also simplified related code to prefer use of JID objects instead of
strings so they don't need to be parsed multiple times.

Closes issue #183

All plugins may now simply define a session_bind method where disco
features and other actions which require the bound JID may be done.

To ensure that disco info, or any settings which depend on the bound
JID, are correct, only set such information on or after the
session_bound event has fired.

Fix for the RSM iterator

There are still a few remaining items in the RFCs to add support for,
but the current plugin support matches the advanced client profile.

Registering this plugin will load the plugins required for advanced
client compliance status.

These values are perisisted across replies.