Change changelog format
Update cpanfile
Checking in changes prior to tagging of version 0.20.

Changelog diff is:

diff --git a/Changes b/Changes
index a197022..6f77fee 100644
--- a/Changes
+++ b/Changes
@@ -1,6 +1,8 @@
 Revision history for Algorithm::HyperLogLog

 {{$NEXT}}
+
+0.20 2013-06-23T09:09:42Z
     - Change dependency
     - Switch aurhoring tool to Minilla