lyb FEATURE print/parse node flags

To allow completely transparent printing
and loading data.
diff --git a/src/printer_lyb.c b/src/printer_lyb.c
index 860d5a0..df7a1c5 100644
--- a/src/printer_lyb.c
+++ b/src/printer_lyb.c
@@ -914,6 +914,9 @@
         LY_CHECK_RET(lyb_print_attributes(out, (struct lyd_node_opaq *)node, lybctx->lybctx));
     }
 
+    /* write node flags */
+    LY_CHECK_RET(lyb_write_number(node->flags, sizeof node->flags, out, lybctx->lybctx));
+
     /* write node content */
     if (!node->schema) {
         LY_CHECK_RET(lyb_print_opaq((struct lyd_node_opaq *)node, out, lybctx->lybctx));