Add a @OptionMenuItem annotation to inject MenuItem

Referred to #560 and #549

This PR add a `@OptionMenuItem` which allows the developer to inject a MenuItem (android or ActionBarSherlock) into an activity.

The developer should just be aware that injection is done in `onCreateOptionsMenu()` so the fields will be set only when the menu is displayed (immediately if an ActionBar is provided, otherwise when the user press the Menu button)