Added a new group_fieldsets option to TranslationAdmin to group fieldsets by translation fields. An approach to issue #38. Based on initial code by Chris Adams. Adopted and enhanced for the latest admin refactoring. The new option currently defaults to False and has to be activated on demand.
Moved group_fieldsets to class.
Sorted translation fields by fieldname.
Updated contributors.
Honoured options like exclude for translation fields and assured that we don't end up with empty fields in untranslated fieldsets.
Added unittest for group-fieldsets functionality in TranslationAdmin.
Small optimization, don't loop twice over trans_fields.
Updated changelog.
Added documentation for the TranslationAdmin.group_fieldsets option.
Fixed missing newline.
Used code blocks consistently.