Checking in changes prior to tagging of version 0.18.

Changelog diff is:

diff --git a/Changes b/Changes
index 3af06ef..4eb3dc9 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Perl extension HTML::TreeBuilder::LibXML

 {{$NEXT}}

+0.18 2013-05-09T01:27:46Z
+
+    - implemented matches(), parent(), guts() node method
+      (Carlos Fernando Avila Gratz)
+
 0.17

     handle /(de)?objectify_text/ for <script> extraction