Version 3.2.0

• Switch from argparse to click (#80)
  • Commandline interface is now documented
  • Salmon now exits with non-zero return codes (#112)
• Fix error in the way default values were handled on start and log commands (#126)
• Minor fixups of commandline help
• salmon.server.QueueReceiver now uses threads (#67)
  • For those using @nolocking, this will mean massive improvements in performance
• salmon.queue.Queue now implements __len__
• Remove nosetests and just use Python's builtin unit test modules (#96)
• Directories required for Salmon startup will now be created if they don't exist (#111)
• Fix routes, blast, and cleanse commands (#102, #103)
• Python 3.8 is now supported
• Import settings file on routes command (#128)