plugin system, first draft: - widgets are now handled with plugins, ContactList and WidgetSelector have been changed to be pluggins - everything in PLUGIN_INFO (including PLUGIN_INFO itself) is optional. Best guess is used if a value is missing - WidgetsHandler use default widget from plugins, which is WidgetSelector for now - PLUGIN_INFO is used in the same way as for backed plugins, with (for now) following possible keys: - "name": human readable name - "description": long description of what widget do - "import_name": unique short name used as reference for import - "main": main class name - "factory": callback used to instanciate a widget (see Cagou._defaultFactory) - "kv_file": path to the kv language file to load (same filename with ".kv" will be used if key is not found) other data should be added quickly, as a path to a file used as icon - host.getPluggedWidgets can be used to find loaded widgets. except_cls can be used to excluse a class (self.__class__ usually) - fixed host.switchWidget when old widget is already a CagouWidget - CagouWidget header new display the available widgets