To save you opening a new link to read my commit message(including spelling errors) I'll post it here as I feel it's important.
Adding all tracks from all albums of an artist is possible. I wouldn't
suggest doing so as the sorting of the table is pretty poor. The inbuilt
sort of the table providid by PyQt4 is unaware of what else exists in thetable in different columns.
What does "pretty poor" sorting of a table looks like? Like this:
Notice that the "sort by track#" is dumb. It does that explicitly even though you would expect it to sort by track# per album (I know that's what I think it should be).
However, although it's not guaranteed, you may get this desired sorting if you sort by album like this:
So, the short of it? The feature is there but not as you or I want it.