Contains all the router classes who decide how to handle the messages.
All router classes must be in this package and must extend the
{@link routing.MessageRouter} (when creating new routers, extending
{@link routing.ActiveRouter} might make ense) class so they can be
dynamically loaded to the simulator. The classes to load can be specified
trough {@link core.Settings} class' settings source. See MessageRouter class and
classes extending it for details about the settings.