Issue #428 - Fix server address settings change so it properly logs out the current account, if any.

Fixes #428, but without new tests.

So much of the sever address change logic is tied to view activity that I can't manageably implement tests. While functional tests might be an expedient way to test it, in this case that the code should be refactored to put more of the logistical activity in the account model, where it would be easily susceptible to unit testing. Issue #429 is tied to the post-3.0 release for that purpose.

I suspect that there is other view code that could be refactored for similar purposes.