* ietf-netconf yang module added with candidate, validate, startup and xpath features enabled.

* Added urn:ietf:params:netconf:capability:yang-library:1.0
* Thanks SCadilhac for helping out, see https://github.com/clicon/clixon/issues/39
* uri_percent_encode() and xml_chardata_encode() changed to use stdarg parameters

lib/src/clixon_yang_module.c

@@ -153,6 +153,7 @@ x            +--ro namespace           inet:uri
                +--ro name        yang:yang-identifier
                +--ro revision    union
                +--ro schema?     inet:uri
+ * @see netconf_create_hello
  */
 int
 yang_modules_state_get(clicon_handle    h,