* Add calculation script field and create line field to trade model line view.
* Modify quantity field on trade model line view to display floating number only if quantity property has value and is not set to None.
* Modify resource field on trade model line and allow users to choose Product document.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@30948 20353a03-c40f-0410-a6d1-a30d3c3de9de