bump grunt-contrib-uglify to ~0.7.0

package.json

@@ -47,7 +47,7 @@
     "grunt-contrib-jshint": "~0.10.0",
     "grunt-contrib-less": "~0.12.0",
     "grunt-contrib-qunit": "~0.5.2",
-    "grunt-contrib-uglify": "~0.6.0",
+    "grunt-contrib-uglify": "~0.7.0",
     "grunt-contrib-watch": "~0.6.1",
     "grunt-csscomb": "~3.0.0",
     "grunt-exec": "~0.4.6",