[Ur] local urls for the script directive

[Edward Z. Yang]

Excerpts from Adam Chlipala's message of Thu Apr 26 08:05:32 -0400 2012:
> This is certainly typical so far.  It might make sense to build some 
> abstraction of deployable resource bundle on top of Ur/Web, perhaps 
> following some cross-language standard that already exists.  But it's 
> awfully nice not to have to build standard HTTP file serving into the 
> Ur/Web implementation to any significant extent. :)

A story for deployment is very important for practical use.  What I point my
"resources" to will vary depending on whether or not I'm testing or in
production, and having to edit my urp file to deploy is very annoying.

Edward