Update time-grunt to v0.3.1.

package.json

@@ -57,7 +57,7 @@
     "grunt-sed": "~0.1.1",
     "load-grunt-tasks": "~0.4.0",
     "markdown": "~0.5.0",
-    "time-grunt": "~0.2.10"
+    "time-grunt": "~0.3.1"
   },
   "engines": {
     "node": "~0.10.1"