Grunt newer

This PR changes some Grunt tasks to only run when their src files have changed. I'm still fucking around with this, but it looks super cool. Already cut ~3 seconds off the normal grunt dist task—nearly half! Would love to cut this down even more.

Grunt plugin: https://www.npmjs.org/package/grunt-newer

Gruntfile.js

@@ -443,11 +443,11 @@ module.exports = function (grunt) {
   grunt.registerTask('test', testSubtasks);
 
   // JS distribution task.
-  grunt.registerTask('dist-js', ['concat', 'uglify']);
+  grunt.registerTask('dist-js', ['newer:concat', 'newer:uglify']);
 
   // CSS distribution task.
   grunt.registerTask('less-compile', ['less:compileCore', 'less:compileTheme']);
-  grunt.registerTask('dist-css', ['less-compile', 'autoprefixer', 'css_flip', 'csscomb', 'less:minify', 'cssmin', 'usebanner']);
+  grunt.registerTask('dist-css', ['less-compile', 'autoprefixer', 'newer:css_flip', 'newer:csscomb', 'less:minify', 'cssmin', 'usebanner']);
 
   // Docs distribution task.
   grunt.registerTask('dist-docs', 'copy:docs');

package.json

@@ -54,6 +54,7 @@
     "grunt-html-validation": "~0.1.13",
     "grunt-jekyll": "~0.4.1",
     "grunt-jscs-checker": "~0.4.0",
+    "grunt-newer": "~0.6.0",
     "grunt-saucelabs": "~5.0.1",
     "grunt-sed": "~0.1.1",
     "load-grunt-tasks": "~0.4.0",