Updated default styles from v8 to v9. Deprecated the MGLMapView class methods in favor of new methods that take a version parameter. Deprecated Emerald outright in favor of Outdoors. Replaced usage of the unversioned MGLStyle methods with the corresponding versioned methods and MGLStyleCurrentVersion to ensure consistency.
Expanded MGLStyle unit tests to also assert that MGLStyle has the right number of style URL methods and that they’re all public. Linked the OS X SDK unit test bundle to libmbgl-core.a. Removed an unnecessary dependency on osxapp.
Replaced Emerald with Outdoors in iosapp and osxapp.
Fixes the iOS and OS X side of #4577 and #4702.
Moved mbgl::util::default_styles to a more appropriate location, where iOS platform code can also find it. Moved -[MGLMapView bundledStyleURLs] (which is now deprecated) and the style switcher in iosapp to default_styles.
Added a collection of convenience methods for getting style URLs. It makes little sense to layer an enum atop this, as MapKit does, because MGLMapView styles aren’t limited to this set. A good analogy is UIColor. This also makes for a good entry point for future runtime styling APIs.
Introduced independent constants for each default style, because it’s more common to need access to a particular style than to iterate over them. This fact is apparent in the MGLStyle class, which now uses macros and assertions to ensure that it’s kept up-to-date with changes in default_styles.
/ref #1462
