remove unused variable
remove unused attribute
turn class attributes into object attributes

BBCParser is a singleton anyway, so there is no need for cumbersome initialization of static attributes.
normalize SIGNAL + SLOT signatures
store a MarbleModel* as attribute in AbstractWeatherService rather than passing it every time
merge createServices() into c'tor
trust AbstractDataPluginModel::setFavoriteItems() to trigger an update
remove WeatherModel::updateItems() and use AbstractDataPluginModel::clear()

clear() already asks the world for repaint, which triggers a refresh in the WeatherModel.
tiling
debug++
use www.geonames.org rather than the deprecated ws.geonames.org server

* seems to deliver more results