When matching against multiple disc release we should match to discs with same no of tracks first.
Currently we just start with cd1, sometimes we can get invalid match to an earlier cd, and even though we have moved some checking to earlier it can still fail at later stage without giving us the chance to check the correct CD. (Only applies when checking one set of songs from a cd/folder against multiple cd release) so we never get a match
Now we process each medium in turn, we then get each subfolder containing same number of tracks and check them in alphabetical against cd1 in order, if no match we try other subfolders.
Then we continue to cd2 and so on