Make readme more clear and fix typos

- Cleaned up the ‘introduction’ to be a bit more clear.
- Made the instructions a proper ordered list
- Added a ‘Bourbon family’ section, as seen in the [Refills repo](https://github.com/thoughtbot/refills)
Definitely. Do you feel that the wording is not clear to still indicate that Normalize could/should be used _with_ Bitters?