[Ur] Latest build does not work with demo

[Christopher Done]

Hi,

I'm completely new to Ur, just trying out the demo instructions here:
http://www.impredicative.com/ur/demo/

With the latest build here: http://www.impredicative.com/ur/urweb-20120329.tgz

But I apart from the -noEmacs option not being available (presumably
removed and replaced with a -emacs option?), it fails to build the
demo due to parse errors:

http://hpaste.org/67324

I don't really know what this replacing dcolon with twiddle means.
Anyway, I will continue through the tutorial and experiment, just
giving you guys a heads up!

Ciao!