Fix u1 search results to not seem too random. Also fix potential crasher.
This was rooted in the fact that musicsearch.ubuntu.com returns a mix of artists, albums, and tracks in the results. We do not show artists, so if the results contains mainly that, then we're screwed (even though there could be many potential track/album matches outside the fetched results). Luckily newer versions of the webservice contains some parameters to tweak this behaviour. This commit makes us use that.
In addition to using the new musicsearch API I also lowered memory churn quite considerably by removing the need to create a lot of Track/Album objects and do excessive string copying.
Nice, I find the presentation of results now more consistent with the rest of ulm - albums first, then individual tracks.
> Also fixed a bug where we'd pass possibly-null strings into a DeeModel. This could have been the root cause of bug #917974.
Actually null strings are handled fine by dee, I remember very well that the special casing for null strings to cause trouble when I was trying to optimize parts of dee, therefore the attached bug is a different issue and we can revert:
60 + model.append (uri != null ? uri : "",
61 + artwork_path != null ? artwork_path : "",
62 + PURCHASE_CATEGORY,
63 + mimetype != null ? mimetype : "",
64 + title != null ? title : "",
65 + artist != null ? artist : "",
66 + dnd_uri != null ? dnd_uri : "");