[FIX] delivery_carrier_label_dispatch - save picking dispatch label pdf file as attachement of the picking
[ADD] an option on wizard to regenerate all pickings' labels
[FIX] get_pdf_label make sure it returns only last created labels and only labels of existing packs.
[IMP] use the new tracking_ids parameter to print only labels for packs in the current dispatch.

As a dispatch does not necessarily contains all the packs from a picking, we do no longer group the labels by packs, we directly generate the labels of the packs sorted by pack
ensure that the packs are always sorted according to the packs name so they are in a consistent order in the pdf
use the general method and not the one for the button
avoid utils.PdfReadError('Cannot read an empty file') error
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
Merge pull request #28 from guewen/7.0-delivery_carrier_label_dispatch-output-file-yvr

delivery_carrier_label_dispatch - save picking dispatch label pdf file as attachement of the picking