Implement "mark for listing" checkbox using schemaextender.
Implement custom setter, which sets/unsets the marker interface.
Make sure content ist not marked by default.
Make sure the catalog is up-to-date.
No longer mark content automatically if an addressblock is added.
Fix openlayers viewlet (replace IOrgunitMarker with IListingMarker).
Reformat test_ics_view (fix several violations).
Remove IOrgunitMarker condition (EventPage -> get address block).
Replace IOrgUnitMarker with IListingMarker in authorities_view.
Update Readme and Changelog.
Upgrade step, which migrates the marker interface.
Protect the new mark_for_listings field with his own permission.
Update translations
Add lawgiver action group: "toggle-marker-interface"
Update readme: wording.
Replace IOrgUnitMaker interface import by using its dottedname.
Rename interfaces: Use IAuthoritySupport and IAuthority
Merge pull request #144 from 4teamwork/mle-mark-for-listings

Implement new behaviour, how to  mark contente for listings.