rename csv_file->strtok_r to csv_strtok_r to make -03 compilation happy
truc
make get_single_ip fill a struct  ip_addr instead of struct subnet
this is more logical

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
add a addr2str helper

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
teach st_printf about struct ip_addr
(it could be cast a struct subnet but ...)
make sure the v_* is not NULL
add a command 'echo' to convert in line IPs

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
add last_ip & first_ip functions
they MODIFY their input

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
teach st_printf about %N (network address) and %B  (broadcast address)
broadcast doesnt exist in IPv6, can be called last

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
teach route_print_fmt about %N and %B addresses
update comment (last_ip/first_ip modify their argument)

Signed-off-by: Etienne Basset <etienne.basset@ensta.org>
Update README (advances in FMT)
add help for the 'echo' command
tr / to - if any in file names