Fixed issue #585. Sort group members by first name or last name in group detail view according to config variable
Merge pull request #589 from normanjaeckel/SortingOnGroupDetailView

Fixed issue #585. Sort group members by first name or last name in group...
Protection for participant managers, Issue #122

Raises a validation error, if a non-superuser user edits himself and
removes the last group containing the permission to manage participants
Merge pull request #591 from normanjaeckel/WarningRechtAufRechte

Protection for participant managers, Issue #122
New Overlay API
Merge pull request #592 from ostcar/overlay

New Overlay API
fixed error on new overlay api
Merge pull request #593 from ostcar/master

Fixed Error in new Overlay API
New Feature: List of speakers.
Updated template and some minor fixed for list of speakers. Updated projector slide.
List of speakers. Part 2
Merge pull request #588 from ostcar/speaker_list

List of speakers