Fix UI performance

[pca006132]

1. Revert Album track list bug #237 and fix the bug regarding divider.
2. Use a single outer RecyclerView for SearchFragment, which removes the need for NestedScrollView.
3. Use a single RecyclerView for ArtistPageFragment, which removes the need for NestedScrollView.
4. Fix download page filtering/grouping.

For 3, my server does not have fancy features such as related artists. So need someone else to test that.

[iBrake]

Something that I've noticed switching from tempo to tempus, is that the track will start playing well before the UI updates. Is this related?

It sounds like a small thing (and I suppose it is), but what happens is that a new song is playing, I go "what the hell is this rubbish" look at the song and it's one of my favourite artists. Then the screen updates and I realise it's a different song. I'd say it's only a 2ish second delay, but it's irritating.

[eddyizm]

@iBrake

Something that I've noticed switching from tempo to tempus, is that the track will start playing well before the UI updates. Is this related?

It sounds like a small thing (and I suppose it is), but what happens is that a new song is playing, I go "what the hell is this rubbish" look at the song and it's one of my favourite artists. Then the screen updates and I realise it's a different song. I'd say it's only a 2ish second delay, but it's irritating.

I don't recall if I seen that happen however that is pretty annoying. I am not sure if it is related but it could be. It would be good to see if we could recreate that scenario but is that something you can consistently recreate ?

[iBrake]

Unfortunately broke my phone, but when I get a replacement I'll see if it's easily recreated.