Checking in changes prior to tagging of version 0.13.

Changelog diff is:

diff --git a/Changes b/Changes
index 02dad86..ec6d2df 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,10 @@ Revision history for Test::LocalFunctions

 {{$NEXT}}

+0.13 2013-05-31T11:21:12Z
+        - Added function to get the back end module name which is used.
+          (Thank you for your advice, @tokuhirom)
+
 0.12 2013-05-30T18:56:21Z
         - Change environment variables for testing.