Checking in changes prior to tagging of version 0.20.

Changelog diff is:

diff --git a/Changes b/Changes
index a765069..b42e8fa 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,10 @@ Revision history for Perl extension Test-Kantan

 {{$NEXT}}

+0.20 2014-03-09T13:07:43Z
+
+    - Refactor interface.
+
 0.19 2014-03-07T03:56:19Z

     - use Module::Spy 0.03 interface.