Cicerone#setRouterFabic suggestion

[Buckstabue]

Currently, in order to create a cicerone instance with a custom router, one has to pass a custom router instance on every Cicerone creation and it's very easy to forget to pass it and default router would be created. I suggest to introduce a static setter for a custom router fabric which is used when calling Cicerone.create(). This approach is used by many libraries