title: No injectable members-error when using more than one dagger module in project
body: <p>I would really like to implement Dagger in my app but I have a hard time to understand how it should be configured correctly.
  I have two classes that I would like to inject. </p>
  
  <pre><code>public class LoginController {
      @Inject Bus bus;
      @Inject Context context;
      // more code 
  }
  
  public class LoginFragment {
      @Inject Bus bus;
      // more code
  }
  </code></pre>
  
  <p>If I put all my code in one module it works fine:</p>
  
  <pre><code>@Module(injects = {LoginController.class, LoginFragment.class})
  public class BasicModule {
  
      @Provides
      @Singleton
      public Bus busProvider() {
          return new Bus();
      }
      @Provides
      public Context provideContext() {
          return RblMobileApp.getContext();
      }
  }
  </code></pre>
  
  <p>But when I put those methods in two different modules (BasicModule and TestModule) I get compiler errors:</p>
  
  <pre><code>@Module(injects = {LoginController.class, LoginFragment.class})
  public class BasicModule {
      @Provides
      @Singleton
      public Bus busProvider() {
          return new Bus();
      }
  }
  
  Error:(18, 8) java: No injectable members on android.content.Context. Do you want to add an injectable constructor? required by rblmobile.controllers.LoginController for rblmobile.injection.BasicModule 
  
  @Module(injects = {LoginController.class})
  public class TestModule {
      @Provides
      public Context provideContext() {
          return RblMobileApp.getContext();
      }
  }
  
  Error:(13, 8) java: No injectable members on com.squareup.otto.Bus. Do you want to add an injectable constructor? required by rblmobile.controllers.LoginController for rblmobile.injection.TestModule
  </code></pre>
  
  <p>So basically I'm told that BasicModule doesn't deliever Context and TestModule doesn't deliever Bus. Why does the ObjectGraph not know that the respective Constructor is in the other module?</p>
  
  <p>Thanks</p>
  
  <p>EDIT:
  That's the method where the ObjectGraph gets created.</p>
  
  <pre><code>public static void init(final Object... modules) {
      Log.i(TAG, "initializing object graph");
  
      if (objectGraph == null) {
          objectGraph = ObjectGraph.create(modules);
      } else {
          objectGraph = objectGraph.plus(modules);
      }
  }
  </code></pre>