Checking in changes prior to tagging of version 0.13.

Changelog diff is:

diff --git a/Changes b/Changes
index 41e8755..b2924de 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,10 @@ Revision history for Perl extension Monoceros

 {{$NEXT}}

+0.13 2013-05-22T06:16:38Z
+
+  - add max-keepalive-connection option
+
 0.12 2013-05-20T07:25:35Z

   - refactoring worker->manager socket passing