Map snapshotter bindings

[ear7h]

Some dependencies for this are in the constructor

MapSnapshotter(FileSource* fileSource,
                   std::shared_ptr<Scheduler> scheduler,
                   const std::pair<bool, std::string> style,
                   const Size&,
                   const float pixelRatio,
                   const optional<CameraOptions> cameraOptions,
                   const optional<LatLngBounds> region,
                   const optional<std::string> cacheDir = {});