code: protected String paramsAsUrlString() {
          StringBuilder bob = new StringBuilder();
          bob.append('?');
          MultiList<String> params = params();
          for (String key : params.keySet()) {
              for (String value : params.list(key)) {
                  bob.append(key);
                  bob.append('=');
                  bob.append(value);
                  bob.append('&');
              }
          }
          bob.deleteCharAt(bob.length()-1); //removes the last '&'
          return bob.toString();
      }
docs: Creates a URL-ready String of the current parameters.
  This includes the starting '?' and '&amp;' as delimiter.
  Example:
  Parameters: key1=[param1, param12], key2=[param2]
  This translates into:
  ?key1=param1&amp;key1=param12&amp;key2=param2
  
  @return URL String of the parameters
  @author MTD