password popup dialog for failed logins

[Antoine Martin]

If we connect to a server and receive a "login failed" message and we haven't got a password, popup to ask the user.
Make it throttled and a configurable option (that can be toggled from the popup) to prevent being DoSed? by fake local mDNS servers swarming us.


Is it worth keeping track of the servers we have already authenticated against to avoid sending a password to a malicious server? (we kinda do via the server key signature)