Small refactor to injection of webworks.js

- changed to document.head
- added error handler and alert if things go south

lib/scripts/bootstrap-blackberry.js

@@ -20,18 +20,19 @@
 */
 
 document.addEventListener("DOMContentLoaded", function () {
-    var wwjs;
     switch(require('cordova/platform').runtime()) {
     case 'qnx':
-        wwjs = document.createElement("script");
-        wwjs.type = "text/javascript";
+        var wwjs = document.createElement("script");
         wwjs.src = "local:///chrome/webworks.js";
         wwjs.onload = function () {
             document.addEventListener("webworksready", function () {
                 require('cordova/channel').onNativeReady.fire();
             });
         };
-        document.getElementsByTagName("head")[0].appendChild(wwjs);
+        wwjs.onerror = function () {
+            alert('there was a problem loading webworks.js');
+        };
+        document.head.appendChild(wwjs);
         break;
     case 'air':
         require('cordova/channel').onNativeReady.fire();