core: dynamics menus refactoring: - menu now use generic callback system, with extra data - asyncMenuCall is removed in favor of launchAction - menu_id (== callback_id) is used to identify menu instead of category/name/type tuple - i18n is managed throught deferred translation, and returned with _i18n suffix e.g.: menu (D_('File'), D_('Open')): (u'File', u'Open') is menu_path, (u'Fichier', u'Ouvrir') is french menu_path_i18n. - type actually can have the following values: - NORMAL: classical menu - JID_CONTEXT: contextual menu, used with any jid - ROSTER_JID_CONTEXT: like JID_CONTEXT, but restricted to jids in roster. - ROSTER_GROUP_CONTEXT: contextual menu, use with groups - security_limit is used, in the same way as for parameters - when using importMenu, callback can be an actual callback, or one already registered with registerCallback