Fix bug on empty headers
Fix bug of delimiter/headers not updating in admin mode
Change the __gar__ behavior: also collects None fields.
__gar__ special attribute no longer flatten uncollected data (now a list)
Update release notes
Update tests
Fix bug of None key_fields represented as "None" in CLI
Fix bug of uninitialized variable on None paths
Forbid empty delimiter when asking questions
Extend custom readers for empty delimiter
Merge branch 'public' into develop