Fixes Wiki change notification mail contains invalid diff link
present correct questions for deletion of documents
Adds a comment explaining why the version is incremented by 1
Adds a spec that tests the wiki_content_updated method
Merge pull request #1042 from opf/fix/migration_correct_attachement_deletion_message

present correct questions for deletion of documents
Update CHANGELOG.md
Merge pull request #1041 from netfighter/bugfix/4701_wiki_change_notification