Added `allowAutomaticFetchingForNewFeedbackForManager:` which allows the developer to influence if the SDK should fetch for new messages on app startup and when the app is coming into foreground.
By default the SDK always checks in those cases if there are already messages existing.
Goal: make BITFeedbackComposeViewControllerDelegate usable for the view controller used by BITFeedbackListViewController
- The delegate is automatically set to the global BITHockeyManager delegate
- When invoking your BITFeedbackComposeViewController, it is possible to overwrite the delegate
