Add empty ignore array to standard config

- This version of grunt-standard requires SOMETHING to be set here, or it dies
  hard because it tries to push undefined into the array of ignored paths

package.json

@@ -156,6 +156,7 @@
     "test": "node script/test"
   },
   "standard": {
+    "ignore": [],
     "parser": "babel-eslint",
       "globals": [
         "atom",