Prepare 3.2.3 release

CHANGES.txt

@@ -1,5 +1,5 @@
-Next 3.x Release
-----------------
+3.2.3 (2016-03-19)
+------------------
 
 - 400 Bad Request is now returned if an XML-RPC request is received with
   invalid body data.  In previous versions, 500 Internal Server Error

supervisor/version.txt

@@ -1 +1 @@
-3.2.2
+3.2.3