convert y standard coordinate to TMS method

Author: osbornb

src/main/java/mil/nga/geopackage/tiles/TileBoundingBoxUtils.java

@@ -443,6 +443,18 @@ public static int tilesPerSide(int zoom) {
 		return (int) Math.pow(2, zoom);
 	}
 
+	/**
+	 * Get the standard y tile location as TMS
+	 * @param zoom
+	 * @param y
+	 * @return
+	 */
+	public static int getYAsTMS(int zoom, int y){
+		int tilesPerSide = tilesPerSide(zoom);
+		int tmsY = tilesPerSide - y - 1;
+		return tmsY;
+	}
+	
 	/**
 	 * Get the zoom level from the tiles per side
 	 *