make a complete list of contributors who hold copyright (and those who
don't).
the case of ted is particularly interesting - he recently disclaimed
significant contributions, but it turns out that this isn't true:
the rewrite in 130664b6 incorporated significant portions of his async
IMAP patch for debian.
speaking of debian, i deleted ted's and nicolas' mention as debian
maintainers, as debian/ is basically just a (poorly maintained) mirror,
and has an own copyright file.
locking cleanups from Oswald Buddenhagen <ossi@kde.org>
* don't need to stat the lockfile since it will always be size 0
* only remove lockfile when we actually succeeded in locking