Fix: proposal_mediafiles table should be called delegateable_mediafiles table
mediafile model: more DRY
mediafile: test __repr__
model: mediafiles to comments assignment.
medifile regression bug
ui to add images comments (javascript only)
adhocracy_kotti_medicenter: new image scales
Merge branch 'feature-315-kotti-cms-for-static-content_mediacenter' of github.com:liqd/adhocracy into feature-315-kotti-cms-for-static-content_mediacenter