report exceptions via exit code
report exceptions via exit code

Now it is possible to handle failed syncs in scripts.

Signed-off-by: Alex Kapranoff <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@kapranoff.ru>
Signed-off-by: Nicolas Sebrecht <347709267ddd1958560c4c317ea3fd613f10a719@laposte.net>

frioux/offlineimap,frioux/offlineimap