libyang CHANGE add LY_VALUE_LYB

Add a separate value format of the LYB representation of the type.
Some of the callbacks API of the type plugins was modified to reflect the
need of passing generic (binary) data representation of the value.
diff --git a/src/parser_lyb.c b/src/parser_lyb.c
index f588bd6..c6a2674 100644
--- a/src/parser_lyb.c
+++ b/src/parser_lyb.c
@@ -456,6 +456,7 @@
         *prefix_data = set;
         break;
     case LY_VALUE_JSON:
+    case LY_VALUE_LYB:
         /* nothing stored */
         break;
     default: