* change accounting_period_workflow: Assignee can start / stop accounting periods, but only Assignor can close them definitely. Also make it possible to cancel open period, and to delete a draft period.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@19492 20353a03-c40f-0410-a6d1-a30d3c3de9de