0.8

This release includes a number of breaking changes meant to improve and simplify Commandant's design.

Improved

• CommandTypes now specify an OptionsType, which is parsed automatically (#41). Thanks @mdiep!
• Unrecognized arguments will now cause an error (#40). Thanks @ikesyo!
• Positional arguments can now be specified using Arguments (#42). Thanks @ikesyo!

Thank you to @NachoSoto, @ikesyo, @mdiep, and @norio-nomura for reviewing pull requests!