Preserve and present what the user understands as their login name in the
settings Account info screen.  If the username is different than the login
name, present both.

(It may be unnecessary, from the user's point of view, to present both.
I'm not well enough acquainted with use of blue/enterprise accounts to know
whether it's a totally internal detail, and/or whether it would be useful
debugging info, so I'm erring on the side of completeness.)
Merge pull request #277 from SpiderOak/issue-276-sensible-settings-username

Preserve and present what the user understands as their login name in the