npm: specify which versions of node we wish to use

Don't use 5.0.0 yet.

package.json

@@ -81,6 +81,6 @@
     "time-grunt": "~1.2.1"
   },
   "engines": {
-    "node": ">=0.10"
+    "node": "4.2.x || 4.1.x || 0.12.x || 0.10.x"
   }
 }