Require grunt in prepublish script only if we have to

Author: rosen-vladimirov

prepublish.js

@@ -1,10 +1,10 @@
 var fs = require("fs"),
-	path = require("path"),
-	grunt = require("grunt");
+	path = require("path");
 
 var pathToTypeScriptEntryPoint = path.join(__dirname, "lib", "ios-sim.ts");
 if (fs.existsSync(pathToTypeScriptEntryPoint)) {
-	var callback = function(err) {};
+	var callback = function(err) {},
+		grunt = require("grunt");
 
 	grunt.cli.tasks = ["ts:devlib"];
 	grunt.cli(null, callback);