cmake . -DNO_AVAHI=1

and lanftpd won't be linked against avahi, or require any avahi files

* Porting oftpd to cmake
* stor support for the incoming directory
* mkd (make directory) support for the incoming directory
* killing all the autohell files
* updating the manpage
* adding avahi (zeroconf) support to announce the ftp on the local network
* several little bugs fixed