• Add faster SIMD UTF-8 validation (GH #213, Zhang Boyang)
  https://github.com/cyb70289/utf8, MIT.
  
• Fix tests for yath (GH #255, with H.Merijn Brand): the test files now
  work with Test2::Harness instead of only Test::Harness, and a yath
  run is added to make xtest when yath is installed.
  
• Skip one t/117_numbers.t test on Perls with 32-bit IVs (GH #254,
  Jeremy Hansen).