* Document how highlight updates works in the optimizing performance page - closes#360
* Change example animated gif to not mention Redux
* Be more explicit about the theory and workflow around using Highlight Updates - closes#360
* improve grammar, correctly label link to #avoid-reconciliation
* Trim content to its essentials and move to a more relevant place in Avoid Reconciliation section - Closes#360
* Make requested changes to wording and host images internally
* Minor rewording
Adds a new docs website, built with Gatsby JS, to replace the old Jekyll site. Source code for the new site lives in /www (although markdown and YML data still comes from the legacy /docs folder).
Changes to either markdown or website source code can be previewed on Netlify. The react-js bot should automatically add comments to each PR with preview links. (This preview is generated by running the newly-added yarn build:docs command in the root package.json.)
The majority of the changes in this PR are contained within the new /www directory. However some minor modifications have been made to existing content in the /docs directory:
* Modified frontmatter author block to always be an array
* Small markdown formatting tweaks
As of Chrome 58, the Timeline tab is now called the Performance tab, this updates the "Optimizing Performance > Profiling Components with Chrome Performance" section of the docs to reflect that.