Add user factory
Add editors service
Parse editors/annotators in TreebankRetriever
Add arethusaUser directive
Add editors directive
Make known when editors are present in editors
Update editors directive template
Add editors to helpPanel
Add translations for editors service and directive
Fix editors.editorsPresent
Fix link target in arethusaUser template
Update link (<a>) styling in arethusa.scss
Fix size of about section in helpPanel
Merge pull request #511 from latin-language-toolkit/editors

Adds editors service, User factory and displays them in the helpPanel