uid of this axis on the brain.
This means that if we do group_by_section_category=True, the brains will have
an attribute section_category_uid that will be the uid of the section category
for this brain.
Also add support for select_dict and select_list to have the same feature when
grouping on a related key.
Fix typo from r37215, group_by_project_category was not working


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@37257 20353a03-c40f-0410-a6d1-a30d3c3de9de