Merge pull request #3601 from odoo-dev/8.0-wmsstagingx-jco

WMS STAGING X
- scheduler cursor and company_id
- digits in transfer wizard
 - delivery putting carrier on picking from sale and correctly invoicing it
- inventory import: imported lines should not be deleted
- average price correction for twice same product / variants
- recreate picking from sale order
- manual purchase order: picking type by default should depend on user's company