add setting xmpp_strip_resource to ignore the resource part of a JID in queries

[cdidier]

Code not reviewed.

One drawback: it prevents irssi-xmpp to query a resource directly, thus chatting will always notify all remote clients.

[ailin-nemui]

I was thinking another way might be to implement a query tracker that renames the query window to the last used resource

[simmel]

One additional feature might be to hide the resource until a messages from multiple resources (aka a "conflict") is a fact.

[simmel]

I've resolved the conflict here https://github.com/simmel/irssi-xmpp/commit/6d635a9372a693d23a9e25a4635f5edfaf1594dd.patch

[ailin-nemui]

http://anti.teamidiot.de/static/nei/*/Code/Irssi/merge_resources.pl