1. Do not duplicate release annotations if they're identical to the last bit.

• Current behaviour: Identical release annotations are duplicated and separated by "----".

2. Merge differing release annotations according to the order of the merged releases/mediums.

• Current behaviour: The order seems to be arbitrary, e.g. medium 4 ---- medium 2 ---- medium 3 ---- medium 1.*

Maybe the latter corresponds with the no less arbitrary order that can be seen in edit reviews, e.g. http://musicbrainz.org/edit/21777500 (2 - 1 - 3) or http://musicbrainz.org/edit/21777564 (1 - 3 - 2), or elsewhere. When merging releases, for instance, the selected releases are not sorted by name nor by order of selection.