Add N5Writer.deleteBlocks method with trivial default implementation

This should be handled by a dedicated DatasetAccess method

Author: tpietzsch

src/main/java/org/janelia/saalfeldlab/n5/N5Writer.java

@@ -327,6 +327,24 @@ boolean deleteBlock(
 			final String datasetPath,
 			final long... gridPosition) throws N5Exception;
 
+	/**
+	 * Deletes the blocks at the given {@code gridPositions}.
+	 *
+	 * @param datasetPath dataset path
+	 * @param gridPositions a list of grid positions
+	 * @return {@code true} if any of the specified blocks existed and was deleted
+	 * @throws N5Exception if any of the block exists but could not be deleted
+	 */
+	default boolean deleteBlocks(
+			final String datasetPath,
+			final List<long[]> gridPositions) throws N5Exception {
+		boolean deleted = false;
+		for (long[] pos : gridPositions) {
+			deleted |= deleteBlock(datasetPath, pos);
+		}
+		return deleted;
+	}
+
 	/**
 	 * Save a {@link Serializable} as an N5 {@link DataBlock} at a given offset.
 	 * The

src/main/java/org/janelia/saalfeldlab/n5/shard/DatasetAccess.java

@@ -34,6 +34,9 @@ public interface DatasetAccess<T> {
 
 	void writeBlocks(PositionValueAccess kva, List<DataBlock<T>> blocks) throws N5IOException;
 
+//	TODO:
+//	  boolean deleteBlocks(PositionValueAccess kva, List<long[]> positions) throws N5IOException;
+
 
 	/**
 	 *