parse_qs(): Make more robust.
Handle request query string. Requires req.parse_qs() to prepare for access.
Release 0.6.4.
sendfile(): Open files in binary mode.
sendfile(): Add minimal auto-detection of mime type.

For HTML and CSS, as required to make browsers render corresponding files
properly.
sendfile(): When file not found, render HTTP 404 response.
Release 0.7.