Update devDependencies.

package.json

@@ -29,7 +29,7 @@
     "grunt": "~0.4.5",
     "grunt-autoprefixer": "~3.0.0",
     "grunt-banner": "~0.6.0",
-    "grunt-contrib-clean": "~0.6.0",
+    "grunt-contrib-clean": "~0.7.0",
     "grunt-contrib-compress": "~0.14.0",
     "grunt-contrib-concat": "~0.5.1",
     "grunt-contrib-connect": "~0.11.2",
@@ -39,12 +39,12 @@
     "grunt-contrib-htmlmin": "~0.6.0",
     "grunt-contrib-jshint": "~0.11.2",
     "grunt-contrib-sass": "~0.9.2",
-    "grunt-contrib-uglify": "~0.10.0",
+    "grunt-contrib-uglify": "~0.11.0",
     "grunt-contrib-watch": "~0.6.1",
     "grunt-csscomb": "~3.1.0",
     "grunt-html": "~5.0.0",
     "grunt-jekyll": "~0.4.2",
-    "grunt-jscs": "~2.3.0",
+    "grunt-jscs": "~2.4.0",
     "grunt-sed": "twbs/grunt-sed#v0.2.0",
     "load-grunt-tasks": "~3.3.0",
     "time-grunt": "~1.2.0"