switch to grunt-css-flip for RTL CSS generation

Gruntfile.js

@@ -201,7 +201,7 @@ module.exports = function (grunt) {
       }
     },
 
-    cssFlip: {
+    css_flip: {
       rtl: {
         files: {
           'dist/css/<%= pkg.name %>-rtl.css': 'dist/css/<%= pkg.name %>.css'
@@ -390,7 +390,6 @@ module.exports = function (grunt) {
 
   // These plugins provide necessary tasks.
   require('load-grunt-tasks')(grunt, {scope: 'devDependencies'});
-  grunt.loadTasks('./grunt/tasks/');
 
   // Docs HTML validation task
   grunt.registerTask('validate-html', ['jekyll', 'validation']);
@@ -419,7 +418,7 @@ module.exports = function (grunt) {
 
   // CSS distribution task.
   grunt.registerTask('less-compile', ['less:compileCore', 'less:compileTheme']);
-  grunt.registerTask('dist-css', ['less-compile', 'cssFlip', 'less:minify', 'cssmin', 'csscomb', 'usebanner']);
+  grunt.registerTask('dist-css', ['less-compile', 'css_flip', 'less:minify', 'cssmin', 'csscomb', 'usebanner']);
 
   // Docs distribution task.
   grunt.registerTask('dist-docs', 'copy:docs');

grunt/tasks/css-flip.js

-/*!
- * Bootstrap Grunt task for generating RTL CSS from LTR CSS using css-flip
- * http://getbootstrap.com
- * Copyright 2014 Twitter, Inc.
- * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
- */
-'use strict';
-
-var flip = require('css-flip');
-
-
-module.exports = function(grunt) {
-  grunt.registerMultiTask('cssFlip', 'Generates RTL CSS from LTR CSS using css-flip', function () {
-    this.files.forEach(function (f) {
-      var unflippedCss = grunt.file.read(f.src);
-      var flippedCss = null;
-      try {
-        flippedCss = flip(unflippedCss);
-      }
-      catch (err) {
-        grunt.fail.warn(err);
-      }
-      grunt.file.write(f.dest, flippedCss);
-      grunt.log.writeln('File ' + f.dest.cyan + ' created.');
-    });
-  });
-};

package.json

@@ -47,6 +47,7 @@
     "grunt-contrib-qunit": "~0.4.0",
     "grunt-contrib-uglify": "~0.4.0",
     "grunt-contrib-watch": "~0.5.3",
+    "grunt-css-flip": "^0.1.0",
     "grunt-csscomb": "~2.0.1",
     "grunt-exec": "~0.4.5",
     "grunt-html-validation": "~0.1.13",