Fixed some conflicts again, as well as adding a connection option to choose the requested protocol version (as discussed in[1]). This new connection option is not useful when connecting to any of the supported postgres versions. But it can be useful when connecting to PG versions before 9.3. Or when connecting to connection poolers or other databases that implement the postgres protocol but do not support the NegotiateProtocolVersion message.
[1]: https://www.postgresql.org/message-id/flat/CAGECzQRrHn52yEX%2BFc6A9uvVbwRCxjU82KNuBirwFU5HRrNxqA%40mail.gmail.com#835914cbd55c56b36e8e7691cb743a18
