0.6.0.0 pm: importing, dynamic passwords and shell prompts

  * add dynamic passwords to the passowrd manager
  * add password manager importing
  * fix bugs in the PasswordManager `amLoggedIn` and `passwordValid`
    (they were throwing exceptions rather than returning False)
  * add support for shell prompts to the password manager
  * expose the optparse-applicative PasswordManager CLI parser and abstract
    syntax for cleaner embedding in optparse-applicative parsers
  * hope dependent pacakges have stopped breaking the Hackage build