libyang CHANGE review header includes

The plugins_types.h was supposed only for implementing data type plugins
code, so I've removed it from libyang.h (now it is supposed to be
included explicitly).
diff --git a/src/printer_xml.c b/src/printer_xml.c
index f3d2c52..994496a 100644
--- a/src/printer_xml.c
+++ b/src/printer_xml.c
@@ -22,13 +22,15 @@
 #include "context.h"
 #include "dict.h"
 #include "log.h"
+#include "out.h"
+#include "out_internal.h"
 #include "parser_data.h"
 #include "plugins_types.h"
-#include "out_internal.h"
 #include "printer_data.h"
 #include "printer_internal.h"
 #include "set.h"
 #include "tree.h"
+#include "tree_data.h"
 #include "tree_schema.h"
 #include "xml.h"