re #787 - Fixed un-scheduling
re #787 - Convert time to GMT
re #787 - Use created_on for articles that don't have a publish_on yet (drafts)
re #787 - Combine publish_on and created_on fields so the drafts are also shown in the list
re #787 - Added published_on column otherwise it was not possible to unpublish articles
re #787 - Typo
Merge branch 'feature/787-publish'