Fixed a typo (i assume) in an error message

FreeBSD-specific fixes

netinet/in.h is required for struct sockaddr_in

Update for Debian pakage creation

requires sys/types.h

main.c:739:24: error: variable has incomplete type 'struct sockaddr_in'
    struct sockaddr_in serv_addr;

Placed to default directory.
User now not need to specify server key with -k server.pub

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