improve transformation report dialog to make possible to select the category we want in the report :
This report can be huge and take a lot of time to generate. But sometime we don't need to make the report on every category but just on some of them. This permit to have a faster report in this cases.
In case nothing is selected, it's the same that if everything was selected (same behaviour than before).

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@33787 20353a03-c40f-0410-a6d1-a30d3c3de9de