Checking in changes prior to tagging of version 1.4.12.

Changelog diff is:

diff --git a/Changes b/Changes
index afa384a..4e3224a 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Perl extension App::plenv

 {{$NEXT}}

+1.4.12 2013-04-15T05:43:50Z
+
+    - Added `plenv --version`
+      (Suggested by miyagawa++)
+
 1.4.11 2013-03-31T03:43:53Z

     - pass test option to Perl::Build