Rework keepalive to use time.sleep() instead of event.wait()

[offlineimap] / README

OfflineIMAP
Copyright (C) 2002 - 2006 John Goerzen <jgoerzen@complete.org>
This software comes with ABSOLUTELY NO WARRANTY; see the file
COPYING for details.  This is free software, and you are welcome
to distribute it under the conditions laid out in COPYING.

http://software.complete.org/offlineimap/

Please see manual.txt; the information previously in README has been moved
there.