Move httpd.js to the main directory

Since the httpd.js seems to be fairly generic, I think we can move it into the repository root.

Still to do, add functionality to copy files from setup/* to the site root as necessary.

The only bad part is that httpd.js is only designed to support a single site.
Fix request-level Error catching
Add a debug mode and add short arguments
Add a function for listing setup/distribution data directories
Add documentation about rendering/parsing forms
Add details on parsing HTTP requests to design docs
Add newlines to design docs