Update dependencies, including Babel to v6 and zeroUnits fix.

Gruntfile.js

@@ -58,8 +58,7 @@ module.exports = function (grunt) {
     babel: {
       dev: {
         options: {
-          sourceMap: true,
-          modules: 'ignore'
+          sourceMap: true
         },
         files: {
           'js/dist/util.js'      : 'js/src/util.js',
@@ -77,7 +76,7 @@ module.exports = function (grunt) {
       },
       dist: {
         options: {
-          modules: 'ignore'
+          extends: '../../js/.babelrc'
         },
         files: {
           '<%= concat.bootstrap.dest %>' : '<%= concat.bootstrap.dest %>'
@@ -87,8 +86,8 @@ module.exports = function (grunt) {
 
     stamp: {
       options: {
-        banner: '<%= banner %>\n<%= jqueryCheck %>\n<%= jqueryVersionCheck %>\n+function ($) {\n',
-        footer: '\n}(jQuery);'
+        banner: '<%= banner %>\n<%= jqueryCheck %>\n<%= jqueryVersionCheck %>\n+function () {\n',
+        footer: '\n}();'
       },
       bootstrap: {
         files: {
@@ -102,8 +101,7 @@ module.exports = function (grunt) {
         // Custom function to remove all export and import statements
         process: function (src) {
           return src.replace(/^(export|import).*/gm, '');
-        },
-        stripBanners: false
+        }
       },
       bootstrap: {
         src: [
@@ -165,10 +163,7 @@ module.exports = function (grunt) {
 
     cssmin: {
       options: {
-        // TODO: disable `zeroUnits` optimization once clean-css 3.2 is released
-        //    and then simplify the fix for https://github.com/twbs/bootstrap/issues/14837 accordingly
-        compatibility: 'ie9',
-        keepSpecialComments: '*',
+        compatibility: 'ie9,-properties.zeroUnits',
         sourceMap: true,
         // sourceMapInlineSources: true,
         advanced: false