Changes:
- Use css prop on the element to style it
- Add webpack + babelrc configuration to remove otherwise needed import boilerplate [according to glamor docs](https://github.com/threepointone/glamor/blob/master/docs/createElement.md)
Rationale: The killer feature of glamor that makes it so great is that it relieves you from naming classes/styles if you use the custom css prop. Together with the babel plugin you also don't need any extra import wherever the css prop is used.
All the real world uses I've seen of glamor has used the css props so I think the example should reflect this. As an example here is docs how to use glamor with gatsby (using the css prop):
https://www.gatsbyjs.org/docs/glamor/
* Examples: clarify language around Yarn create & npx
* add missing READMEs and create-next-app usage
* suggest people tag jthegedus in firebase related issues
* add yarn alt instructions
* cerebraljs example readme & fixes
* remove global npm install of create-next-app
* add npx to create-next-app command in examples
* add bash to shell snippets
* add yarn create to next-app command in examples
* fix READMEs named with lowercase
* change READMEs to use UPPERCASE
