Minor usability fixes

Exercism Command-Line Interface (CLI)

Exercism takes place in two places: the discussions happen on the website, and you work on exercises locally. The CLI bridges the gap, allowing you to fetch exercises and submit solutions to the site.

This is a stand-alone binary, which means that you don't need to install any particular language or environment in order to use it.

To install, download the archive that matches your operating system and architecture, unpack the archive, and put the binary somewhere on your path.

You will need to configure the CLI with your Exercism API Key before submitting.

For more detailed instructions, see the CLI page on Exercism.

Recent Changes

This mostly updates usage strings and various feedback after running commands to make the tool easier to use.