Bump Clojure to 1.9.0-alpha17; Use clojure.spec.alpha

[solussd]

• Updated all usage of clojure.spec to clojure.spec.alpha
• Fixed formatting issue (specifically, those causing parinfer trouble)

[mtnygard]

Master diverged far enough that I decided to do this by hand on the current head. Closing this PR, since it's now done.

Thanks @solussd!