v3.0.3

Changelog
To automate the build process a bit, I've added some new features.

• Added flexgrid-utils.scss with an override for the $enable-utils variable
• Updated webpack.config.js with a new entry for flexgrid-utils.scss
• Updated the README reflecting these changes
• Removed the package-lock.json as npm will run fine without, and we already have a yarn.lock

The following files will now be generated upon running yarn run build:

flexgrid.css            # regular CSS
flexgrid.map.css        # map file
flexgrid.min.css        # minified version

flexgrid-utils.css      # regular CSS including margin utilities
flexgrid-utils.map.css  # map file for margin utilities
flexgrid-utils.min.css  # minified version including margin utilities

Also, since 3.0.2 this project is being built on Netlify, Travis CI, and CircleCI to make sure the code isn't breaking.