Merge branch 'develop' of https://github.com/almende/vis into develop

Conflicts:
	dist/vis-light.js
	dist/vis.js

gulpfile.js

@@ -47,6 +47,10 @@ var webpackConfig = {
     filename: VIS_JS,
     sourcePrefix: '  '
   },
+  // exclude requires of moment.js language files
+  module: {
+    wrappedContextRegExp: /$^/
+  },
   plugins: [ bannerPlugin ],
   cache: true
 };

index.js

@@ -63,3 +63,7 @@ exports.network = {
 exports.Graph = function () {
   throw new Error('Graph is renamed to Network. Please create a graph as new vis.Network(...)');
 };
+
+// bundled external libraries
+exports.moment = require('./lib/module/moment');
+exports.hammer = require('./lib/module/hammer');