Have the universal signup form set its own referral value

[ondrae]

The universal signup form can be embedded in other sites due to the great work of @davidrleonard

I'm using it in the v3 version of the Brigade site, but I'm having to set my own referral link.

In the included javascript that goes with the form, it should detect its own url and use that.

Something like $('input[name=REFERRAL]').val(location.pathname);