Added remote validation

Added remote validation with AdditionalFields functionality that MVC's
[Remote()] attribute uses.
Access this via "data-remote-route", "data-remote-msg", and
"data-additional-fields"

MVC sample:

@Html.TextBoxFor(model => model.Email, new { data_validators="required,
remote, email", data_placeholder="remote validation",
data_remote_route=Url.Action("DoesUserEmailExist"),
data_remote_msg="Email is already in use"})