add requirable 'calendars' module + include it in main bundle

Author: etpinard

lib/calendars.js

@@ -0,0 +1,11 @@
+/**
+* Copyright 2012-2016, Plotly, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+'use strict';
+
+module.exports = require('../src/components/calendars');

lib/index.js

@@ -54,4 +54,9 @@ Plotly.register([
     require('./groupby')
 ]);
 
+// components
+Plotly.register([
+    require('./calendars')
+]);
+
 module.exports = Plotly;