1.2.0.0

What's Changed

• Improve test suite by @tfausak in #52
• Sort modules within mixins by @tfausak in #53
• Clarify stability of Haskell API by @tfausak in #55
• Allow input to influence output by @tfausak in #56
• Don’t overwrite input when it’s already formatted by @tfausak in #58

Full Changelog: 1.1.4.0...1.2.0.0