Support es6 classes in gulp build

Based on https://gist.github.com/danharper/3ca2273125f500429945

Author: sman591

.jshint

@@ -17,5 +17,6 @@
   "strict": true,
   "globals": {
     "define": true
-  }
-}
+  },
+  "esversion": 6
+}

gulpfile.js

@@ -1,7 +1,10 @@
 'use strict';
 
 var gulp = require('gulp');
-var browserify = require('gulp-browserify');
+var babel = require('babelify');
+var browserify = require('browserify');
+var source = require('vinyl-source-stream');
+var buffer = require('vinyl-buffer');
 var cssmin = require('gulp-cssmin');
 var download = require('gulp-download');
 var exec = require('child_process').exec;
@@ -119,13 +122,16 @@ gulp.task('demo', function () {
 	buildStyles('demo');
 	buildStyles('bootstrap-multiselect');
 
+	var bundle = browserify('./demo/src/App.js', {
+		debug: true
+	}).transform(babel.configure({
+		presets: ['es2015', 'react']
+	}));
+
 	// scripts
-	gulp.src('./demo/src/App.js')
-		.pipe(browserify({
-			debug: true,
-			transform: ['reactify']
-		}))
-		.pipe(rename('demo.debug.js'))
+	bundle.bundle()
+		.pipe(source('demo.debug.js'))
+		.pipe(buffer())
 		.pipe(gulp.dest('./demo/www/js/'))
 		.pipe(uglify())
 		.pipe(rename('demo.min.js'))

package.json

@@ -27,9 +27,12 @@
     "react": ">=15.0.0"
   },
   "devDependencies": {
+    "babel-preset-es2015": "^6.24.1",
+    "babel-preset-react": "^6.24.1",
+    "babelify": "^7.3.0",
     "bootstrap": "^3.3.7",
+    "browserify": "^14.3.0",
     "gulp": "^3.9.1",
-    "gulp-browserify": "^0.5.1",
     "gulp-connect": "^5.0.0",
     "gulp-cssmin": "^0.1.7",
     "gulp-download": "0.0.1",
@@ -43,7 +46,9 @@
     "jsxhint": "^0.15.1",
     "react-bootstrap": "^0.30.3",
     "react-dom": "^15.3.1",
-    "reactify": "^1.1.1"
+    "reactify": "^1.1.1",
+    "vinyl-buffer": "^1.0.0",
+    "vinyl-source-stream": "^1.1.0"
   },
   "keywords": [
     "react",