If selected, send client certificate before password auth

[gaionim]

Changes seems harmless to me except userInfo pack and unpack.

widget for client certificate is always visible

all auth type ( I've tested only plain) sends cliantCertificateAlias
for me works both with certificate ( my server)
and without cert ( gmail)

userInfo pack and unpack seems weak, but I lack skills to fix

[cketti]

Thanks for your work! I like the feature.

But extending the already horrible mechanism of storing credentials in URIs is not an option. We need to change the way we store server settings/credentials first. And only then add more authentication combinations. I created issue #793 to track this feature.