Make Iq exceptions more discoverable and simpler to use.

IqError and IqTimeout now extend XMPPError, so if you don't care
about the difference, you can use:

    try:
        self.do_something_with_iqs()
    except XMPPError:
        # Error? Timeout? I don't care!
        pass

If you do need to distinguish between timeouts and error replies,
you can still continue to use:

    try:
        self.do_somethin_with_iqs()
    except IqError as err:
        pass
    except IqTimeout:
        pass

If you don't catch any Iq errors and you're processing a stanza
then an error response will be sent, just like normal if you raise
XMPPError or any other exception, except that the error messages
will be generic to prevent leaking too much information.

sleekxmpp/stanza/rootstanza.py

@@ -10,7 +10,7 @@ import logging
 import traceback
 import sys
 
-from sleekxmpp.exceptions import XMPPError
+from sleekxmpp.exceptions import XMPPError, IqError, IqTimeout
 from sleekxmpp.stanza import Error
 from sleekxmpp.xmlstream import ET, StanzaBase, register_stanza_plugin
 
@@ -43,23 +43,41 @@ class RootStanza(StanzaBase):
         Arguments:
             e -- Exception object
         """
-        if isinstance(e, XMPPError):
-            self.reply(clear=e.clear)
+        if isinstance(e, IqError):
+            # We received an Iq error reply, but it wasn't caught
+            # locally. Using the condition/text from that error
+            # response could leak too much information, so we'll
+            # only use a generic error here.
+            self.reply()
+            self['error']['condition'] = 'undefined-condition'
+            self['error']['text'] = 'External error'
+            self['error']['type'] = 'cancel'
+            log.warning('You should catch IqError exceptions')
+            self.send()
+        elif isinstance(e, IqTimeout):
+            self.reply()
+            self['error']['condition'] = 'remote-server-timeout'
+            self['error']['type'] = 'wait'
+            log.warning('You should catch IqTimeout exceptions')
+            self.send()
+        elif isinstance(e, XMPPError):
             # We raised this deliberately
+            self.reply(clear=e.clear)
             self['error']['condition'] = e.condition
             self['error']['text'] = e.text
+            self['error']['type'] = e.etype
             if e.extension is not None:
                 # Extended error tag
                 extxml = ET.Element("{%s}%s" % (e.extension_ns, e.extension),
                                     e.extension_args)
                 self['error'].append(extxml)
-                self['error']['type'] = e.etype
             self.send()
         else:
-            self.reply()
             # We probably didn't raise this on purpose, so send an error stanza
+            self.reply()
             self['error']['condition'] = 'undefined-condition'
             self['error']['text'] = "SleekXMPP got into trouble."
+            self['error']['type'] = 'cancel'
             self.send()
             # log the error
             log.exception('Error handling {%s}%s stanza' %