The error bubbles through the event processing loop, breaking it and
hanging the application.
Instead, there is now a .exception(e) method on XMLStream which may
be overridden or reassigned that will receive all unhandled exceptions
(read: not XMPPError) from event and stream handlers.
If a stanza handler raised an exception, the exception was processed
and replied by the modified stanza, not a stanza with the original
content.
A copy is now made before handler processing, and if an exception occurs
it is the copy that processes the exception using the original content.
This allows exceptions to include the original
content of a stanza in the error response by including
the parameter clear=False when raising the exception.
* check_stanza does not require stanza_class parameter. Introspection!
* check_message, check_iq, and check_presence removed -- use check
instead.
* stream_send_stanza, stream_send_message, stream_send_iq, and
stream_send_presence removed -- use send instead.
* Use recv instead of recv_message, recv_presence, etc.
* check_jid instead of check_JID
* stream_start may accept multi=True to return a new SleekTest instance
for testing multiple streams at once.
Raising an XMPPError exception from an event handler now works, even if
from a threaded handler.
Added stream tests to verify.
We should start using XMPPError, it really makes things simple!
