convert level string to Level

lib/logger.js

@@ -1,5 +1,6 @@
 "use strict";
 var debug = require('./debug')('logger')
+, levels = require('./levels')
 , util = require('util');
 
 module.exports = function Logger(dispatch, category) {
@@ -44,6 +45,6 @@ function LoggingEvent (category, level, data) {
   this.startTime = new Date();
   this.category = category;
   this.data = data;
-  this.level = level;
+  this.level = levels.toLevel(level);
 }