fix MapView, so tile provider can be accessible

add MapViewTileProviderBase::maximumLevel()

libs/map/mapview_tile_provider_osm.h

@@ -33,8 +33,9 @@ public:
 	~MapViewTileProvider_OSM();
 
 	QString name() const override;
-	bool requestTile(OSM::TileIndex index) override;
+	bool requestTile(MapViewTypes::TileIndex index) override;
 	QSize tileSize() override;
+	int maximumLevel() const override;
 
 protected:
 	void applyParameters() override;