Updates Crashlytics
Updates Simperium to Mark 0.7.1
ContextManager: Adds migrationFailed getter helper
WordPressAppDelegate: nukes Simperium metadata on migration failure
WordPressAppDelegate: Adds note
Merge branch 'release/4.5' into issue/2582-handling-broken-coredata-migrations

Conflicts:
	WordPress/Classes/Utility/ContextManager.m
Merge pull request #2584 from wordpress-mobile/issue/2582-handling-broken-coredata-migrations

Handling broken coredata migrations