Let’s hear it for the Springs School’s fourth-grade opera, “Cat Tales” — or “Ton of Fun 61 Opera” — which was performed four times at Guild Hall this month. Imagine, 61 kids divided into small groups, writing a libretto, composing music, building sets and doing lighting, working on makeup, sewing costumes, and handling promotion. I’ve been to lots of kids’ productions over the years, including some directed by theater professionals, and you can take it from me: This was extraordinary.