Consolidates addTrait calls into one single call

plugins/c9.ide.analytics/mock_analytics.js

@@ -14,7 +14,7 @@ define(function(require, exports, module) {
 
         plugin.freezePublicAPI({
             log: function() {},
-            addTrait: function() {},
+            addTraits: function() {},
             alias: function() {},
             identify: function() {},
             track: function() {},

plugins/c9.vfs.standalone/www/test.js

@@ -162,7 +162,7 @@ require([
                 return prefs;
             })(),
             analytics: {
-                addTrait: function() {}
+                addTraits: function() {}
             },
             commands: (function(){
                 var commands = {};