* common: specific code for the racket web pages.

* www: actual content of main site.

* download: content of download site (only installer pages and such)

* */all.rkt: files that just require all the necessary modules to build
  the whole site

* */resources.rkt: files that define the resources for a site (icon,
  css, logo)

* minis: smaller one-source-file sites

* stubs: template "sites" that are intended to be hooked into other
  systems to get the racket look.
