- make feeds a first-class citizen and give them their own class (orthogonal to categories)
- do not involve QString in networking operations, since QByteArray is more than enough (and QDomDocument will handle the encoding so we don't need to do anything about it)
- compatibility with the KNS1 feeds: latest, most downloaded, highest rated are on by default
- describe the two major workflows (uploads and downloads) and mention some minor worksflows