Code review comment for lp:~mhaulo/mixxx/allow-playlist-and-crate-renaming

Hey Mika,

thank you very much for your contribution. I have reviewed your branch and found a bug: Assume you have two playlists "A" and "B". Renaming "B" to "A" will not fail and results in two playlists "A" and "A". Therefore, you must check if the renamed playlist name exists or not. Furthermore, I would like see an UNIQUE constraint on attribute <name> in the <playlist table> (if other developers agree).

@Albert & Developers
I've done a lot of library improvements in my Traktor branch, e.g., n-level tree-structures for child models. If we gonna merge his branch to trunk first, we end up in numerous conflicts when merging Traktor feature in. I recommend to merge his breach into the Traktor feature branch.