Alphabetize variable declarations and assignments

I alphabetized the longer lists of variable declarations and
assignments so they’re easier to follow.
Move base-font-color to 'colors' category
Create variables for error-related styles
Initial commit

This file is designed to store misc. utility classes.
Initial commit

This file stores classes related to displaying messages to the user
(e.g., warning, error, etc.)
Add reference to _utility.scss
Add references to _messages.scss
Rewrite error handling
Update README with setup instructions