Remove usage of graceful-fs

package.json

@@ -36,7 +36,6 @@
     "derequire": "2.0.3",
     "fs-extra": "0.26.6",
     "glob": "6.0.4",
-    "graceful-fs": "4.1.3",
     "handlebars": "4.0.5",
     "jsdoc": "3.4.0",
     "marked": "0.3.5",

tasks/generate-requires.js

@@ -1,4 +1,4 @@
-var fs = require('graceful-fs');
+var fs = require('fs-extra');
 
 // The number of files that we need to generate goog.require's for.
 var numFiles = process.argv.length - 1;