title: Microsoft bing maps api and loading modules issue
body: <p>I'm building a store locator and loading a custom module via require. The custom module is dependent on Directions &amp; Search module from microsoft. I hate the callback hell and want to pre load the modules return a promise and action on the custom module once everything is loaded.</p>
  
  <p>Using bluebird for Promise spec and I've tried several approaches <code>Promise.method</code>, <code>Promise.promisify</code>, <code>new Promise(function(resolve, reject){Microsoft.Maps.loadModule({callback:resolve})})</code> I can't seem to get any of them working.</p>
  
  <p>My latest implementation:</p>
  
  <pre><code>function loadSearch() {
              var resolver = Promise.defer();
              Microsoft.Maps.loadModule('Microsoft.Maps.Search', {
                  callback: resolver.resolve
              });
              return resolver.promise;
          } /* end loadSearch */ 
  
          function loadDirections() {
              var resolver = Promise.defer();
              Microsoft.Maps.loadModule('Microsoft.Maps.Directions', {
                  callback: resolver.resolve
              });
              return resolver.promise;
          }
  
  Promise.all([loadSearch(), loadDirections()], function() {
          //do something
      });
  </code></pre>
  
  <p>results in <code>Uncaught TypeError: Cannot read property '_tryFollow' of undefined bluebird.js</code>
  Can anyone point out what an obvious error in the latest code or a psuedo code example of loading modules in a promise fashion.</p>