Variable styling and a minor comment change

This PR:
- Changes all vars to `lowercase-with-dashes` inline with [this comment](https://github.com/mojotech/jeet/pull/316#issuecomment-53752959).
- Removes back-ticks from a comment.

Maybe we could use this as a general cleanup PR? If you want me to do any other things, let me know.

This will need to be part of v6 as the variable names changing will break stuff.