[ADD] print, print_docsaway, print_sale : module to print and send docum...

...ents by post, implementation for docsaway webservices.

Print and send documents by post
print : provider base module to print account.invoice
print_sale : print and send sale.order
print_docsaway : implementation of docsAway Provider
Use setdefault for this kind of code: dict.setdefault(key, value) returns dict[key] if set, or set key to value and returns values. Here you could do user_to_notify.setdefault(uid, list()).append((my_tuple)) .