Bump version
Grouping to solve parent group filtering breaks on Postgres. Revert (refs #687).
don't confuse field_index with field_id
Fix various issues regarding groups management; fixes #686
Groups manager rights, refs #499, #686

Disable delete, mailings and csv exports buttons on members list.
Allow attendance sheet, labels and card generation.
Display group composition buttons for admins and staff only; fixes #709
Cannot proceed mulitple joins on the same name; fixes #712
Constraint is missing for Postgres databases, do not try to remove it; fixes #681
Restrict some dirs
Only admins or staff can create new groups; refs #709
Update changelog
Merge branch 'hotfix/0.7.5.4'