add QueryTerrainHeight function to AbstractMap (#571)

Looks good.

Author: abhishektrip

sdkproject/Assets/Mapbox/Unity/Map/AbstractMap.cs

@@ -250,6 +250,15 @@ public virtual Vector3 GeoToWorldPosition(Vector2d latitudeLongitude)
 			return _root.TransformPoint(Conversions.GeoToWorldPosition(latitudeLongitude, CenterMercator, WorldRelativeScale).ToVector3xz());
 		}
 
+		public virtual float QueryHeightData(Vector2d latlong)
+		{
+			var _meters = Conversions.LatLonToMeters(latlong.x, latlong.y);
+			var tile = MapVisualizer.ActiveTiles[Conversions.LatitudeLongitudeToTileId(latlong.x, latlong.y, (int)Zoom)];
+			var _rect = tile.Rect;
+			var _worldPos = GeoToWorldPosition(new Vector2d(latlong.x, latlong.y));
+			return tile.QueryHeightData((float)((_meters - _rect.Min).x / _rect.Size.x), (float)((_meters.y - _rect.Max.y) / _rect.Size.y));
+		}
+
 		public abstract void Initialize(Vector2d latLon, int zoom);
 
 		public void Reset()