code: function(source, callback) {
          callback = callback || noop;
  
          //if there's a queue
          if (queue[source] instanceof Array) {
              //just add it
              return queue[source].push(callback);
          }
  
          //otherwise there is not a queue
          //so let's create one
          queue[source] = [callback];
  
          var script = document.createElement('script');
          var head = document.getElementsByTagName('head')[0];
  
          script.async = 1;
  
          head.appendChild(script);
  
          script.onload = script.onreadystatechange = function( _, isAbort ) {
              if(isAbort || !script.readyState || /loaded|complete/.test(script.readyState) ) {
                  script.onload = script.onreadystatechange = null;
                  script = undefined;
  
                  if(!isAbort) {
                      queue[source].forEach(function(callback) {
                          callback();
                      });
  
                      delete queue[source];
                  }
              }
          };
  
          script.src = source;
      }
docs: Gets a script remotely, runs it
  and caches it.
  
  @param string
  @param function
  @return void