FIX jaws.collide with arrays of circles

`jaws.collide` doesn't work when colliding a circle vs a list of circles or a list of circles vs another list of circles. This patch fixes:

- Circles vs Circles collisions in `jaws.collide`
- Two tests in `collision detection` that were commented that tested these circles vs circles case.
- A test in `collision detection with callbacks` that was expecting a non-collision between two colliding circles (?)

PS: I haven't run `build.rb`, so if this pull request gets through, it will need to be re-run.