Additives explorer

[PrajwalM2212]

#1330

[teolemon]

:app:compileObfDebugJavaWithJavac/home/travis/build/openfoodfacts/openfoodfacts-androidapp/app/src/main/java/openfoodfacts/github/scrachx/openfood/views/AdditivesExplorer.java:37: error: AdditivesExplorer is not abstract and does not override abstract method onClick(int,String) in ClickListener
public class AdditivesExplorer extends BaseActivity implements AdditivesAdapter.ClickListener {
       ^
/home/travis/build/openfoodfacts/openfoodfacts-androidapp/app/src/main/java/openfoodfacts/github/scrachx/openfood/views/AdditivesExplorer.java:100: error: method does not override or implement a method from a supertype
    @Override
    ^
/home/travis/build/openfoodfacts/openfoodfacts-androidapp/app/src/main/java/openfoodfacts/github/scrachx/openfood/utils/WifiUploadReceiver.java:96: error: cannot find symbol
            String contentText = this.getResources().getQuantityString(R.plurals.offline_notification_count, listSaveProduct.size(), listSaveProduct.size());
                                                                                ^
  symbol:   variable offline_notification_count
  location: class plurals
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: /home/travis/build/openfoodfacts/openfoodfacts-androidapp/app/src/main/java/openfoodfacts/github/scrachx/openfood/views/MainActivity.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors
 FAILED
FAILURE: Build failed with an exception.

[teolemon]

Thanks @ripetrescu for the review :-)
Merging @PrajwalM2212