title: Reusing modules in angular2 fails
body: <p>Am developing an angular2 website and i have a root module and a sub level module but whatever modules i include in the root module i have to reinclude in the sub level module hence not really reusable</p>
  
  <p>This is hat i have</p>
  
  <p>in the app module</p>
  
  <pre><code>@NgModule({
      declarations: [
         AppComponent,
         ComingSoonComponent,
       ],
     imports: [
        BrowserModule,
        FormsModule,
        HttpModule,
        AppRoutingModule,
        HomepageModule,  //included the homepage module
        OwlModule
  
     ],
   providers: [],
     bootstrap: [AppComponent]
    })
     export class AppModule { }
  </code></pre>
  
  <p>Now in the homepage module</p>
  
  <pre><code>@NgModule({
     imports: [
          CommonModule,
           OwlModule//already in the app module
      ],
      declarations: [HomepageComponent]
    })
   export class HomepageModule { }
  </code></pre>
  
  <p>The owl module is imported twice so that it works but if i import only in the app module then i get an error that</p>
  
  <pre><code> If 'owl-carousel' is an Angular component, then verify that it is part of this module.
  </code></pre>
  
  <p>What could i be missing out since in an application involving multiple modules this can become abit tiresome having to duplicate imports</p>