TODO

                          DChat - Peer-To-Peer Chat over TOR 

  UNDONE
  ------
    * async connections
    * support for contact heart beat
    * support for file sharing
    * check memory leaks with valgrind
    * write protocol specification


  DONE
  ----
    * support `Date` and `Server` headers
    * print illegal header if received pdu is corrupt
    * refactor write_pdu in decoder.c using dchat headers structure
    * support for config files
    * fix /connect inline-command bug when no args are specified 
    * fix bug where no error is thrown if the same required 
      command-line option is given
    * add more checks to decoder and encoder functions
    * comprehensive code refactoring
    * improve implementation of chat commands
    * improve overall stability
    * add section "COMMANDS" in man page
    * adpat DChat protocol, so that nicknames
      will be sent as headers.
    * doxygen documentation with autotools
    * add getopt() in dchat.c
    * re-write usage() in dchat.c
    * fix multiple execution of termination 
      signal handler