feat!: ability to skip outputs

[donn]

• atpg:
  • added automatic netlist to bench conversion via nl2bench if lib file is specified
  • added ability to bypass outputs as well as inputs
• misc:
  • slightly adjusted string representation of Port class
  • fixed bad cli flag descriptions
  • --include is no longer comma-delimited, pass multiple times to define multiple includes
  • reformatted everything using https://github.com/swiftlang/swift-format