remove default size limits from all Constraints

[Brian Warner]

At allmydata, we've been surprised several times now by the default size limits that most container Constraints have. For example, the ListOf? constraint imposes a limit of 30 items.

I added these default sizes based upon my personal expectations of "normal" usage. What I've learned is that this was a pretty narrow point of view, and that everybody else using Foolscap has had different expectations. The biggest problem is the surprise factor: things work great for a while, then after you've tested everything, stuff breaks because the data you're transmitting grows beyond default limits.

So I'm thinking that the type-checking utility of Constraints is independent of their DoS-mitigation utility, and therefore it makes more sense to remove these default size limits.

[Brian Warner]

fixed, in [189d640b132aab3b22f0ff7ac4ae2593a670ffcc]