RoutingTable6: fire change notifications when the routes are changed
RoutingTable: make 'routes' and 'multicastRoutes' fields private

to make sure that subclasses could not violate its invariants.
(These vectors must be sorted according to prefix lengths.)
RoutingTable6 fix: clear cached routes when the interface is down or the routing table changed
InterfaceEntry: replace protocol[34]data with isisdata and trilldata
InterfaceEntry: fix typo
RoutingTable: add watch for 'multicastForward' parameter
RoutingTable6: join to ALL_NODES_2 and ALL_ROUTERS_2 (in routers) multicast group at initialization
RoutingTable6: added 'forwardMulticast' parameter