Email addresses with special characters not correctly encoded

[rjalexander]

Email addresses using special characters (specifically email addresses with a + as part of the local address) are not being correctly encoded in the request to Kickbox.

According to the RFC, valid characters in the local address include:
!#$%&'*+-/=?^_`{|}~

Based on the code in UrlHelper.cs, it looks like the email value is not URI escaped when building the request

          return string.Join("&",
              properties.Select(x =>
                  string.Concat(Uri.EscapeDataString(x.Key), "=", x.Value.ToString())));

This can be reproduced by a request similar to the following:

The value for "Email" is not coming back as sent in the request, and the kickbox Result does not agree with what Kickbox would reply