Allow chaining of Router.addRoute() calls

[kaero]

Existing interface is a bit annoying when writing new router:

router.addRoute({
  ...
});

router.addRoute({
  ...
});

// +100500 route.addRoute calls

I suppose to return router instance from addRoute to allow chaining:

router
    .addRoute({
     ...
    })
    .addRoute({
      ...
    });

Only a bit of sugar, no anything more..

[miripiruni]

+1

[ruslankerimov]

May be add new method: pushRoute, appendRoute or ...
Because returning an instance of created route can be useful and I don't want to break backwards compatibility.