Multiple routers registering same route support (subrouters)

I've talked to you about this in the past, but one of my biggest qualms with Backbone's router is the inability to register the same route more than once. For instance if you were to have a router for two widgets that want to bind to the same route (say posts/); the first wants to render the post the second widget wants to display some statistics on the amount of views on the post

``` js
var AppRouter = Backbone.Router.extend({
routes: {
"posts/:id": "getPost"
}
});

var app_router = new AppRouter;

app_router.on('route:getPost', function( id ){
console.log('router 1', id);
});

var app_router2 = new AppRouter;

app_router2.on('route:getPost', function( id ){
console.log('router 2', id);
});

Backbone.history.start({pushState: false});

app_router.navigate('posts/5', {trigger: true})
```

Only one router registers the navigate =/

Start with the Backbone example in the issue and inspect the router implementations covered by this comparison, tracing how route registration and navigation are handled. Done means the project documents or demonstrates support for multiple routers or widgets receiving the same posts/:id route, with behavior matching the example.

Written by the indexing model from the issue text.