**Make amp example valid**
I'm using amp validator chrome plugin which shows that `meta charset=utf-8` is duplicated.
I assume that `Head` component adds `<meta charset="utf-8" class="next-head next-head">`
anyway.
And this line just duplicating it.
<img width="987" alt="screen shot 2018-06-06 at 15 54 45" src="https://user-images.githubusercontent.com/1488195/41036743-198ca00a-69a2-11e8-978c-5a5cb5a994d2.png">
* 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
* Added Google AMP example
* Added styles and a second page
* Using regular anchor since there is no client-side routing
* Added comment on react config for amp