fix(build): update code to work with latest RxJS changes

src/app/broadcaster.service.ts

@@ -1,8 +1,6 @@
 import { Injectable } from '@angular/core';
-import { Subject } from 'rxjs/Subject';
-import { Observable } from 'rxjs/Observable';
-import 'rxjs/operators/filter';
-import 'rxjs/operators/map';
+import { Observable, Subject } from 'rxjs';
+import { filter, map } from 'rxjs/operators';
 
 interface BroadcastEvent {
   key: any;
@@ -70,7 +68,8 @@ export class Broadcaster {
    */
   on<T>(key: any): Observable<T> {
     return this._eventBus.asObservable()
-      .filter(event => event.key === key)
-      .map(event => <T> event.data);
+      .pipe(filter(event => event.key === key),
+            map(event => <T> event.data)
+      );
   }
 }