Checking in changes prior to tagging of version 2.15.

Changelog diff is:

diff --git a/Changes b/Changes
index b3afde9..fbf15ba 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Perl extension Furl

 {{$NEXT}}

+2.15 2013-05-10T08:40:10Z
+
+    - Added Furl::Response#as_string.
+      (tokuhirom)
+
 2.14 2013-04-19T02:11:43Z

     - Fixed testing issue