reactivate sale_cancel_reason
port models and method to api 8.0
reactivate sale_exceptions modules
port models and methods to api 8.0
Merge pull request #29 from yvaucher/8.0-sale_cancel_reason

8.0 port sale_cancel_reason
Merge pull request #32 from yvaucher/8.0-sale_exceptions

8.0 port sale_exceptions