Simplify root handler

This will not yet be functional, but will be patched up in coming
commits.

Ref #106
Clean up the res/ directory structure

This will allow files to be served directly using a normal HTTP server,
rather than requiring complex multiplexing.

Ref #106
Update links in res/web/

This will make the new directory structure usable. All requests other
than to /api/ and /captcha/ could now be handled by another HTTP server,
such as nginx or lighttpd.

Close #106
Merge branch 'f.better-http-handling' into development