fix generation of picking shipping labels from picking dispatch when there are no pack defined in the pickings
add file extension in file name for poor OS
Add better exception message from dispatch to identify the pack with an error
update pot file
delivery_carrier_label_dispatch - Improve efficiency of label generation by threading it. For instance for postlogistics, using serialized calls to the SOAP web service is a really slow as it would wait for a response before sending the next request.
Fix rst title in manifest
rewrite exception handling for cursor and orm exceptions on generate_labels
Specify Exception class to ensure catching right exceptions and avoid catching SystemExit and KeyboardInterupt exceptions
Fix membership operator