Make TieBreaks into an IEnumerable<TieBreak> again

[ErwanTLG]

So I noticed that the TieBreaks property of the Tournament class was converted to an IEnumerable<TieBreak> in 2c41a0c but this change was rollbacked with 1b6d4a6.

I don't know why it was changed, but I assume it was because it caused some issues because not all the possible values were taken into account. If this is the case, here are the possible values that I found when I did some digging:

• "match wins"
• "game wins"
• "game win percentage"
• "points scored"
• "points difference"
• "match wins vs tied"
• "median buchholz"

On their knowledge base, Challonge also lists custom, however I have not seen it for tie_breaks but only for ranked_by.

[jacobhood]

Hey Erwan, I rolled it back is because I thought modifying the generic type could be a breaking change, and for that reason that it would best be saved for version 2.0.0. I have a couple of other things in mind for that release, but I've been unusually busy recently and haven't gotten around to implementing them. I suppose there's really no reason that change can't be pushed to the repo now though, so I'll do that soon. Thanks for the digging, too.

[jacobhood]

Resolved in commit 872942a8869367385dac4ae8e7fac0bf38ac2f88.