README update: song highlighting implemented

[oleggtro]

I don't really know, what you meant by this, but tried it out on my local machine and it seems to be working fine.
Did someone just forget to update the readme?

[Insprill]

@jpochyla Can you confirm what you mean here?

[jpochyla]

Hi, sure!

Highlight now-playing track only in the correct album / playlist

I don't really know how to approach this. Track is always playing in a context (album, top tracks, search etc), and I think that now-playing track displayed in the now-playing context should look different from track that is technically now-playing (has the same track ID), but is displayed in a different context.

Keep highlighted track in viewport

More straightforward. Auto-scroll to reveal tracks when they start to play, if the mouse cursor is not active (hovering the window or maybe not moving for a while?).

[Insprill]

Closing since those aren't implemented yet