[gxml] Implemented GXml.Document.create_comment

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit db1171df0d7eb4dfbba527c0cc430eaee85049fc
Author: Daniel Espinosa <esodan gmail com>
Date:   Mon May 4 12:37:45 2015 -0500

    Implemented GXml.Document.create_comment

 gxml/Document.vala    |    4 ++--
 vapi/xlibxml-1.0.vapi |    6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/gxml/Document.vala b/gxml/Document.vala
index 4a9d5b0..8adf728 100644
--- a/gxml/Document.vala
+++ b/gxml/Document.vala
@@ -51,10 +51,10 @@ public interface GXml.Document : Object, GXml.Node
    */
   public abstract GXml.Node create_text (string text);
   /**
-   * Creates a new { link GXml.Text}.
+   * Creates a new { link GXml.Comment}.
    *
    * Is a matter of you to add as a child to any other
    * { link GXml.Node}, like a { link GXml.Element} node.
    */
-  //public abstract GXml.Node create_comment (string text);
+  public abstract GXml.Node create_comment (string text);
 }
diff --git a/vapi/xlibxml-1.0.vapi b/vapi/xlibxml-1.0.vapi
index 8590dfd..c524a76 100644
--- a/vapi/xlibxml-1.0.vapi
+++ b/vapi/xlibxml-1.0.vapi
@@ -18,6 +18,12 @@
  * Author:
  * Daniel Espinosa <esodan gmail com>
  */
+
+/**
+ * Utility functions not present in libxml-2.0 bindings to be used internaly.
+ *
+ * Don't use this namespace's functions in your code. Instead, use GXml's public API.
+ */
 [CCode (cheader_filename = "gxml/xlibxml.h")]
 namespace Xmlx {
   [CCode (cname = "gxml_doc_get_intsubset_entities", cheader_filename = "gxml/xlibxml.h")]