add state property
make use of RoutingManager's state property
position attribute is not needed
[API change] have the RoutingModel take Routes rather than GeoDataDocuments

* makes the RoutingModel agnostic to how routes are represented as GeoDataDocuments
simplify
waypoints are only used temporarily
[API change] remove non-const version of RouteRequest::operator[]
port RouteRequest to use GeoDataContainer internally
persistent routing document
debug++
fix crash
add icons
render pixmap via style