xml FEATURE xml parser

just work in progress:
- element name parser (lyxml_get_element())
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6827dc0..403a6b0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -157,7 +157,8 @@
     src/hash_table.c
     src/set.c
     src/context.c
-    src/parser_yang.c)
+    src/parser_yang.c
+    src/xml.c)
 
 #set(lintsrc
 #    tools/lint/main.c