from the useless department:

I implemented seeking in the media player. It was slow as heck so I replaced the code for playing the file with some of my own and now seeking is (on my computer) basically instantaneous.

Click on the progres bar to skip to that point in the song. When you play a song that is still downloading, clicking on 90% of the progress bar takes you to 90% of what you have downloaded already. That means the scale of the progress bar changes as you download, which is weird, but I kinda like it. No chance of clicking on a part you don't have yet. Doing so wouldn't break anything, but I like having it so it just isn't possible.

Just mp3 at the moment, but wav is coming.