Don't touch to unknown fields.
Checking in changes prior to tagging of version 0.02.

Changelog diff is:

diff --git a/Changes b/Changes
index 4d120a5..451781e 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,8 @@
 Revision history for Perl extension Class::Accessor::TrackDirty

+0.02 March 29, 2013
+    - Fix the bug by which to_hash() may break $self.
+
 0.01 February 22, 2013
     - original version; created by dim
       at Sat Feb 16 12:19:36 2013.