Added some nullability qualifiers in method implementation selectors for consistency with declarations.
The user dot view now has a non-zero size. Previously only its layer was sized properly. Also resolved some pedantic warnings about missing designated initializer overrides.
Xcode 6.3 or above is now required for building this project.
Made `+[MGLAccountManager setMapboxMetricsEnabledSettingShownInApp:]` unavailable, with a message explaining what to do instead. Removed a commented-out call to that method. Only the environment for an access token if one hasn’t already been set in Info.plist.
That way there’s no ambiguity about when you should call things like `+[MGLAccountManager setMapboxMetricsEnabledSettingShownInApp:]`. In fact, that method is now deprecated because it’s so easy to call in the wrong place.
Fixes#1535.
