Support for sslverify

We've seen it here and Dave reported to me on IM that he has received
further reports of people getting stuck by the new 8.4 SSL code that
verifies server certificates by default.

I think this will happen for example for everybody who has their pg on a
debian server and their client elsewhere, for example, since debian
enables a snakeoil SSL cert by default (which in itself is a pretty bad
idea, but it's what they do)


Should we provide an option to override this (connection option
sslverify) in the connection dialog? And is it something we need to do
for this version (yes, I know it's already in beta..)

//Magnus