optparse-applicative 0.10.0

• Parser execution and help text generation are now more modular, and allow for
  greater customisation.
• More consistent API for option and argument builders: now option takes
  a reader as argument, and nullOption is deprecated in favour of option.
  The reader modifier is gone. Quick migration guide:
  • option (without a reader modifier) => option auto
  • nullOption (without a reader modifier) => option disabled
  • option/nullOption (with a reader r modifier) => option r.
• Added convenience builder strArgument, equivalent to argument str.
• Removed functions deprecated from at least version 0.8.0.
• Switched test infrastructure to tasty.
• Fixed bugs
  • #63 - Inconsistency between 'argument' and 'strOption' types