smurfy already implemented a favorite manager in the fahrplan2 branch which works for the harmattan ui. The fremantle ui still lacks this feature though its present per se.

Nevertheless the harmattan ui looks very appealing. Well done. You might want to reconsider the idea of using QML for both harmattan and fremantle. Of course a lot of controls and views must be created but I would lend a hand here.

Furthermore a plugin system is (in my opinion) a must have feature for the upcoming fahrplan2. Taking the current state in consideration this shouldn't be too hard to achieve. I'd like to point to my ticket here.

In addition you should think of another way of parsing. At a first glance XPath seems to be inappropriate and will easily break the application.