[Android] [URBNG-274] Add logout functionality

Brief description of changes made and code:
- slightly changed "setLoggedPlayer()" method in Database class to fix error in Logcat: Finalizing a Cursor that has not been deactivated or closed.
- MenuItemHelper is the auxiliary class which main purpose is to avoid code repetition across project
- in "onResume()" method within each activity Menu is invalidated so following scenario will not occur:
  1) user is not logged in and navigates to LoggingInActivity
  2) user logs in
  3) user navigates back to exisiting activities. Without invalidating Menu the "Logout" menu item would remain disabled and user could not log out.