`Default` trait is not implemented for rodeo with spur types other than `Spur` about lasso HOT 1 OPEN

That's a good question, thanks! Originally the concrete types for Default were made with the idea that "Spur is the default type, so that's what Default should make", but I think I just forgot to update the definition of Default when I messed with new(). It still does have the downside that it no longer allows Rodeo::default() to "just work" due to inference, but that probably doesn't matter very much

from lasso.