[ADD] Modules sale_cancel_mrp and sale_mrp_link

OpenERP 7.0 module to cancel a sale order and by the same time,  related manufacturing orders. Uses another module that links the sale order to generated manufacturing orders.

This modules need sale_cancel_picking that you can find on this PR : https://github.com/OCA/sale-workflow/pull/69
You should only test the picking for cancelling the picking and oly testing the manufacturing order for cancelling it