code: function generateURL(url, opt) {
          var keys = XP.match(url, /\{(\w+)\}/g);
  
          XP.forEach(keys, function (key) {
              url = url.replace(key, opt[XP.trim(key, '{}')]);
          });
  
          return url;
      }
docs: *********************************************************************** 
  Generates a request URL from a string with placeholders and the option object
  
  @param {string} url - the url with placeholders
  @param {Object} opt - the map with the placeholders values