v1.3.1

Use new releases of upstream packages.

Fix

(#253) Fix typo in setupTreadleBackend()

(#264) Ensure mill artifact names agrees with sbt's name (for publishing).

(#265) Fix mill issues - Evaluator arguments, scala{check,test} dependencies.

Feature

(#251) Be explicit about scala.io
Use FileUtils instead of ambiguous io.Source

(#260) PeekPokeTesters methods documentation