fix rollup es6, it doesn't need babel transpiling

grunt/rollup.config.js

@@ -1,10 +1,7 @@
-import babel from 'rollup-plugin-babel';
-
 //var external = Object.keys( require( './package.json' ).dependencies );
 
 export default {
   entry: 'js/src/index.js',
-  sourceMap: true,
-  plugins: [babel()]
+  sourceMap: true
   //external: external
 };

grunt/rollup.docs.iife.config.js

@@ -1,8 +1,10 @@
 import config from './rollup.config.js';
+import extend from 'extend'
+import babel from 'rollup-plugin-babel';
 
-config.format = 'iife';
-config.entry = 'docs/assets/js/src/index.js',
-
-config.dest = 'docs/dist/js/docs.iife.js';
-
-export default config;
+export default extend(true, config, {
+  plugins: [babel()],
+  format: 'iife',
+  entry: 'docs/assets/js/src/index.js',
+  dest: 'docs/dist/js/docs.iife.js'
+})

grunt/rollup.es6.config.js

@@ -1,6 +1,7 @@
 import config from './rollup.config.js';
+import extend from 'extend'
 
-config.format = 'es6';
-config.dest = 'dist/js/bootstrap-material-design.es6.js';
-
-export default config;
+export default extend(true, config, {
+  format: 'es6',
+  dest: 'dist/js/bootstrap-material-design.es6.js'
+})

grunt/rollup.iife.config.js

@@ -1,6 +1,9 @@
 import config from './rollup.config.js';
+import extend from 'extend'
+import babel from 'rollup-plugin-babel';
 
-config.format = 'iife';
-config.dest = 'dist/js/bootstrap-material-design.iife.js';
-
-export default config;
+export default extend(true, config, {
+  plugins: [babel()],
+  format: 'iife',
+  dest: 'dist/js/bootstrap-material-design.iife.js'
+})

grunt/rollup.umd.config.js

@@ -1,8 +1,9 @@
-
 import config from './rollup.config.js';
+import extend from 'extend'
+import babel from 'rollup-plugin-babel';
 
-config.format = 'umd';
-//config.moduleName = 'bootstrapMaterialDesign';
-config.dest = 'dist/js/bootstrap-material-design.umd.js';
-
-export default config;
+export default extend(true, config, {
+  plugins: [babel()],
+  format: 'umd',
+  dest: 'dist/js/bootstrap-material-design.umd.js'
+})

package.json

@@ -65,6 +65,7 @@
     "load-grunt-tasks": "~3.3.0",
     "markdown-it": "^5.0.0",
     "mq4-hover-shim": "^0.3.0",
+    "node-extend": "^0.2.0",
     "npm-shrinkwrap": "^200.1.0",
     "rollup": "^0.25",
     "rollup-plugin-babel": "^2.3",