FIX(formatter) use dashes not underscores for message field keys

Author: Petr Matousek

lib/formatter.js

@@ -203,13 +203,13 @@ class Formatter {
 
         //amqp properties
         workDict['id'] = dict['message_id'];
-        workDict['user_id'] = Formatter.castUserId(dict['user_id']);
+        workDict['user-id'] = Formatter.castUserId(dict['user_id']);
         workDict['to'] = dict['to'];
         workDict['subject'] = dict['subject'];
-        workDict['reply_to'] = dict['reply_to'];
-        workDict['correlation_id'] = dict['correlation_id'];
-        workDict['content_type'] = dict['content_type'];
-        workDict['content_encoding'] = dict['content_encoding'];
+        workDict['reply-to'] = dict['reply_to'];
+        workDict['correlation-id'] = dict['correlation_id'];
+        workDict['content-type'] = dict['content_type'];
+        workDict['content-encoding'] = dict['content_encoding'];
         workDict['absolute-expiry-time'] = dict['absolute_expiry_time'];
         workDict['creation-time'] = dict['creation_time'].getTime();
         workDict['group-id'] = dict['group_id'];