[Pidgin] #15508: Support for XEP-0280: Message Carbons

[Pidgin]

#15508: Support for XEP-0280: Message Carbons
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 Reporter:  xnyhps               |       Owner:  deryni
     Type:  enhancement          |      Status:  new
Milestone:                       |   Component:  XMPP
  Version:  2.10.6               |  Resolution:
 Keywords:  xmpp carbons jabber  |
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Comment (by ernierasta):

 Thank you for great patch! After brief testing works very well with latest
 prosody jabber server. I think it should be included in default pidgin.

 I personally think, it would be better to configure it in account
 settings. If you have jabber account with many ad-hoc commands available,
 it is hard to realize where it can be turned on. And if you have jabber
 server with carbons ad-hoc options enabled, you end up with 4 carbon
 related options in account menu. But it is minor thing.

 Great work!

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Ticket URL: <https://developer.pidgin.im/ticket/15508#comment:4>
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