- add a perlish Http_daemon.daemon class, e.g.:
    let d = new daemon ... in
    while true do
      req = d#accept ()
      ...
    done
- parse also header and contents of http requests and add corresponding methods
  to requests objects

- add the possibility to chdir in a given dir before starting     -> DONE
- add support for multi threaded daemon                           -> DONE
- add Http_daemon.respond                                         -> DONE