Now that warnings were almost all removed, let's enable zero-warning
via -dW. All tests were adjusted, but two:
- mcli/mcli_start_progs.vtc:
the programs section currently cannot be silenced
- stats/stats-file.vtc:
the warning comes from the stats file itself on comment lines.
All other ones are now OK.
To follow-up the implementation of the new set-proxy-v2-tlv-fmt
keyword in the server, the connection is updated to use the previously
allocated TLVs. If no value was specified, we send out an empty TLV.
As the feature is fully working with this commit, documentation and a
test for the server and default-server are added as well.
