Merge pull request #24 from saalfeldlab/fix/closeOutputStream

fix: output stream on LockedWriters where not closing themselves

src/main/java/org/janelia/saalfeldlab/n5/s3/AmazonS3KeyValueAccess.java

@@ -609,7 +609,11 @@ public Reader newReader() throws IOException {
 		public OutputStream newOutputStream() throws IOException {
 
 			checkWritable();
-			return new S3OutputStream();
+			final S3OutputStream s3Out = new S3OutputStream();
+			synchronized (resources) {
+				resources.add(s3Out);
+			}
+			return s3Out;
 		}
 
 		@Override