* Prevents adding units to css custom properties

* Fix code style

* Optimize custom property checking

* Prevents adding units to css custom properties in markup creation

* Update passing tests

* Fix argument name and reuse check in DEV

**what is the change?:**
Added an `eslintrc` which disables the 'comma-dangle' rule just for
addons.

**why make this change?:**
To get CI passing again on the 15* branches.

We don't have dangling commas in the addons because it breaks GCC under
certain conditions. This doesn't affect React because we use Babel with
React, but it's not worth setting up Babel for the addons at this time.

**test plan:**
`yarn lint`

**issue:**
None - hopefully will fix this before it's a problem

fixes #9956

To pull in https://github.com/facebook/react/pull/6648/files
fixes https://github.com/facebook/react/issues/9956

In order to add https://github.com/facebook/react/pull/6648/files
fixes https://github.com/facebook/react/issues/9956

* Add addon changes to 15.6.0 changelog

* Oops

* Add to blogpost

* Blog post for 15.6.0

**what is the change?:**
A short and sweet summary of 15.6.0 changes

**why make this change?:**
To thank community contributors and call out important changes.

**test plan:**
Visual inspection.
I also looked it over in a markdown viewer - http://dillinger.io/

**issue:**
https://github.com/facebook/react/issues/9398

* Add 'Installation' and 'Changelog' to 15.6.0 blog post

**what is the change?:**
Added the 'Installation' section we have on most release blog posts,
customized for the 15.6.0 version of React.
Added the 'Changelog' from master to the blog post.

**why make this change?:**
To show folks how to install React and what changes are in this release.

**test plan:**
Visual inspection

**issue:**
https://github.com/facebook/react/issues/9398

* Improvements to blog post, and add self to `authors.yml`

**what is the change?:**
- Add self to contributors so my name turns into a link
- Use backticks for code-ish things
- Second header to ##, not #
- Change production mode link to the new address per @bvaughn's comment
- Update changelog with fixes from https://github.com/facebook/react/pull/9951

**why make this change?:**
Make things more clear and accurate.

**test plan:**
Visual inspect - @flarnie will paste an image of how it appears in the
actual docs.

**issue:**
https://github.com/facebook/react/issues/9398

* Further improvements to 15.6 blog post

**what is the change?:**
- Reword heading about deprecation warning changes
- add 'br' s to the list of installation options
- add some stray missing backticks

**why make this change?:**
Clarity and readability

**test plan:**
Visual inspection

**issue:**
https://github.com/facebook/react/issues/9398

* Minor fixes to 15.6.0 changelog

* Remove remaining double space

* Backticks

* Minor fixes to 15.6.0 changelog

* Remove remaining double space

* Backticks

* Minor fixes to 15.6.0 changelog

* Remove remaining double space

* Backticks

* Build createFragment addon

* Tack the addon onto React.addons object

* Generalize build process for all addons

* Fix lint

* Fix lint again

This reverts commit 1de60827.

**what is the change?:**
`git checkout master -- CHANGELOG.md`
Then made the 15.6 release no longer wrapped in 'details' tag.

**why make this change?:**
We are releasing 15.6 :D

**test plan:**
Visual inspection

**issue:**
https://github.com/facebook/react/issues/9398