fix(index): Replace executeAyncScript with executeScript (#4)

Fixes the issue described in: aurelia/skeleton-navigation#714 (comment)

Previously when the app was larger it would wait to emit the events before
protractor was loaded, however due to the speed increase introduced by
the experimental webpack configuration, aurelia was initialising and emitting
the event before protractor had a chance to listen to it, hence it would hang
indefinitely. Telling the browser to execute the script synchronously will
delay aurelia long enough for protractor to register its listeners before
aurelia emits the event itself.

Author: michaelbull

index.js

@@ -21,7 +21,7 @@ function addValueBindLocator() {
 
 function loadAndWaitForAureliaPage(pageUrl) {
   browser.get(pageUrl);
-  return browser.executeAsyncScript(
+  return browser.executeScript(
     'var cb = arguments[arguments.length - 1];' +
     'if (window.webpackJsonp && document.querySelector("[aurelia-app]")) { cb("Aurelia composed") }' +
     'document.addEventListener("aurelia-composed", function (e) {' +
@@ -33,7 +33,7 @@ function loadAndWaitForAureliaPage(pageUrl) {
 }
 
 function waitForRouterComplete() {
-  return browser.executeAsyncScript(
+  return browser.executeScript(
     'var cb = arguments[arguments.length - 1];' +
     'document.querySelector("[aurelia-app]")' +
     '.aurelia.subscribeOnce("router:navigation:complete", function() {' +