1.2.1

Release 1.2.1

• Fix the handling of the various ways to specify whether tools should limit
  their targets to changed files or run against the entire repository. The
  configuration systems had disagreements on what to call the options in
  question, which resulted in some configuration entries being ignored. We
  enforce a set of validations on reads and writes now to avoid such a problem
  in the future (#89, resolves #88)
• Add coverage-checking, and then improve test coverage and remove unreferenced
  code as a result. (#87)