- automatically define start date and stop date on currency exchange line in order to make it available for the full day.
- allow some document to not be closed when we close the counter date
- the accounting date make all operations after the date working

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@15162 20353a03-c40f-0410-a6d1-a30d3c3de9de