#1 When should tracks automatically be queued?

Right now, when a track is finished, and it is the last item in the queue, the next track in that track's parent group will (if present) be queued. The idea is that if, right after opening mtui, you select the first track in a group and play it, mtui will automatically queue the rest of the group. The problem is that this isn't always what the user wants, and is particularly surprising when a group was previously shuffled.

For example, suppose a group contains 10 items, numbered 1 through 10. When the user selects "play next, shuffled", it will immediately be entirely queued in some random order:

4 7 3 9 1 2 5 10 8 6

Once the track numbered 6 finishes, mtui will automatically queue the track numbered 7, removing it from where it was previously in the queue and placing it up next (then immediately playing it):

4 3 9 1 2 5 10 8 6 7

Once track 7 is finished, mtui will queue 8, and so on, until the following arrangement is reached:

4 3 1 2 5 6 7 8 9 10

Of course, the user would never expect any more tracks to be queued once the end of the shuffle is reached. (It might be expected that the group would re-shuffle, as in re-shuffling and queuing the entire group all over again, but maybe that's a little bit of a stretch.)

My basic "solution", for now, is probably to keep mtui from ever automatically queueing tracks: If you want to play an entire group, just use the context menu and select the option you want.

I made a tweak so that pressing "next track" (n or shift+down) will automatically queue and play the next track (if the current track is at the end of the queue). The use case is starting track 5, then pressing shift+down twice to get to track 7; then, if you want, you can press shift+up twice to get back to track 5, and mtui will play just tracks 5, 6, and 7 (it won't automatically queue 8 or any others).

The main discussion question here is if there should be different modes of automatically adding tracks. Should there, for example, be a way to shuffle a group without immediately adding all of its tracks? Should there be a way to start a group at a certain point, and then play the rest of the tracks in the group? Should mtui return to the previous way auto-mode after a particular task ("play all tracks past a certain point", "shuffle the tracks in this group")? (Answer: yes, if we do anything like this idea.)