[plt-scheme] web-server: base address of error pages

> 3. Base url for errors* is the root directory.

If we get to vote, I vote for this.

> I'm not sure what Apache does

I avoid reading documentation, but a quick look at the source of an  
error page with images, from a site that use Apache suggests that the  
base address is set to the web root.

For example, note that http://www.cs.brown.edu/fo/go, references ./ 
images/dept/blank.gif "which has an absolute path of /images/dept/ 
blank.gif.

-Arjun