Cleared out old uml-graph and moved release notes to their own folder.
Merge branch 'master' of https://github.com/Tietoarkisto/metka
Moved prev/next commands to RevisionController and unified them to 'adjacent' request. Moved json-export to RevisionController and made it into an ajax call similar to DDI-export. Moved DDI export and import to StudyController. Removed GeneralService since all methods were either removed or moved elsewhere.