HoTT/HoTT — pull request #338 by JasonGross (2014-03-10 23:51:22+00:00)
Title: Circle was in Prop.  Now it's not.

Instead it's in Set, which is fine. Also, fix definition of eliminator as per #122.

Since this is a very small change, and someone is waiting on the `Prop` -> `Set` fix, I'm going to push it directly.