Add a builder to create accounting lines.
Add a script used to generate prevision in invoice transaction rule to use the employee as section for employee share; see TestPayroll.test_AccountingLineGeneration for example of use.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@21587 20353a03-c40f-0410-a6d1-a30d3c3de9de