back reference with customer/supplier invoices with shipment
Merge branch 'master' of https://github.com/abhishek-jaiswal/shipment into devel

Conflicts:
	shipment.py
missing doc count
Merge branch 'master' of https://github.com/abhishek-jaiswal/shipment into devel
Merge pull request #1 from abhishek-jaiswal/devel

Devel