The --duration option for coupons create was not working in non-interactive mode so I changed the array to the same format you had the other enums in -- %w( foo bar baz).
Merge pull request #10 from oGLOWo/master

Duration option was not working in non-interactive mode
Finish Usage docs in README, finally! Add descriptions to all remaining undocumented command parameters.
bump patch version level - v1.6.6 release