#1940: Enable support to localizated messages from XMPP server

Description of the bug

When entering in a chatroom, XMPP server sends the message "This room is not anonymous" to client, even if I am using chat in pt_BR language.

XMPP protocol supports localization/internationalization (http://xmpp.org/rfcs/rfc3920.html#i18n) and ejabberd is translated into various langs (http://www.ejabberd.im/localization), then it is possible to have these kind of message localized into language used by client.

I think we have 2 options to do it:

1. Change RubyBOSH to start session defining lang; or
2. Change client through lib Strophe.js to sends message to server using lang

-- JoenioCosta -- 17 Mar 2011