Output all raised Exceptions error strings to the error log. If we are
in debug mode, we also output the traceback of the exception.
Save all exceptions that occur during the run time to a Queue and output
them all again when the offlineimap sync is finished.
Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>