Reorganize AppDelegate, add notifications manager

- Defer appropriate tasks to the background queue

- Add notifications manager class to declutter the AppDelegate

- Remove iOS 6 appearance customization code
Make WPMobileStats track first launch

- Updates NotificationsManager and AppDelegate

- Remove unused or soon to be unused (BetaUIWindow) notifications
Fixed deployment target and xctool builds

xctool was trying to build for iOS6 because the WordPressTest target had
an older target deployment
Updated tests to iOS7 target
Cleanup headers in AppDelegate

- Handle side-effects of doing so in other files
Use AFNetworking for upgrade check
Ignore error for update check
Merge branch 'develop' into issue/609

Conflicts:
	WordPress/Classes/WordPressAppDelegate.m
Final cleanup for App Delegate

- Remove unused properties

- Remove properties that are only ever used for one dead state (isUploadingPost, etc)

- Lazy load file logger
Add method to NotificationsManager for app launch
Fix warnings and rename stats/update check

- The warning fixing should have been picked up from #608 but were not.

- Give a bit more clarity to the stats/update checking via rename
Fix test compilation
Merge branch 'develop' of github.com:wordpress-mobile/WordPress-iOS into issue/609

Conflicts:
	WordPress/Classes/BetaUIWindow.m
	WordPress/Classes/WordPressAppDelegate.m
Merge pull request #629 from wordpress-mobile/issue/609

Clean up App delegate