bpd0018

My thinking was to leave the actual code in place in case the fabled V4 protocol ever happens, but remove the documentation for the parameter so that people don't try...

I have now updated faq.md as requested. Let me know if you agree about leaving the code as is.

I think there are two ways to do that - either just comment the property in PGProperty under the assumption that anyone looking at protocolVersion will find it there or...