Checking in changes prior to tagging of version 0.54001.

Changelog diff is:

diff --git a/Changes b/Changes
index e53bee1..6e2f70c 100644
--- a/Changes
+++ b/Changes
@@ -1,7 +1,11 @@
 Revision history for Perl extension CGI::Header::PSGI.

+0.54001  May 20th, 2013
+
   - Requires CGI::Header 0.54 or higher
   - Overrides finalize() method of the superclass
+  - "0.54001" denotes CGI::Header::PSGI 0.54001 is compatible with
+    CGI::Header 0.54

 0.14  May 14th, 2013
requires CGI::Header 6.62