Checking in changes prior to tagging of version 0.27.

Changelog diff is:

diff --git a/Changes b/Changes
index 0fe3048..43ba02a 100644
--- a/Changes
+++ b/Changes
@@ -1,6 +1,9 @@
 Revision history for Plack-App-Proxy

-0.26    02/26/2012
+0.27    02/26/2013
+        - Remove more HTTP::Headers assumptions
+
+0.26    02/26/2013
         - Add parent dependency

 0.25    11/10/2012