add {{NEXT}} placeholder to Changes
fix tests
Checking in changes prior to tagging of version 2.1.0.

Changelog diff is:

diff --git a/Changes b/Changes
index 5f83652..7a9253e 100644
--- a/Changes
+++ b/Changes
@@ -1,6 +1,10 @@
 Revision history for Mouse

-{{NEXT}}
+{{$NEXT}}
+
+2.1.0 2013-11-26T13:15:54Z
+    - Dropped 5.6.2 support
+    - Migrated to Minilla

 2.0.0 2013-11-06 09:15:00+0900
     [BUG FIXES]