refactor(router): RouteData as a type

BREAKING CHANGE

The ROUTE_DATA token has been removed and replaced with a type RouteData,
allowing a type injection like we do with RouteParams.

Before:

    constructor(routeParams: RouteParams, @Inject(ROUTE_DATA) routeData) {
      let id = routeParams.get('id');
      let name = ROUTE_DATA.name;
    }

After:

    constructor(routeParams: RouteParams, routeData: RouteData) {
      let id = routeParams.get('id');
      let name = routeData.get('name');
    }

Fixes #4392

Closes #4428

modules/angular2/src/router/async_route_handler.ts

@@ -7,7 +7,7 @@ export class AsyncRouteHandler implements RouteHandler {
   _resolvedComponent: Promise<any> = null;
   componentType: Type;
 
-  constructor(private _loader: Function, public data?: Object) {}
+  constructor(private _loader: Function, public data?: {[key: string]: any}) {}
 
   resolveComponentType(): Promise<any> {
     if (isPresent(this._resolvedComponent)) {