Checking in changes prior to tagging of version 0.55.

Changelog diff is:

diff --git a/Changes b/Changes
index 5d2e06e..d5a42ab 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,7 @@
 Revision history for Perl extension CGI::Header.

+0.55 (1.00-RC8) May 22nd, 2013
+
   - Add CGI::Header::Standalone again as the alternative to CGI::Header

 0.54 (1.00-RC7) May 20th, 2013