Fix docs (#2482)

* Fix #2414, address part of #1687

Also cleared the CSS up to be a lot more readable instead of smooshed
into a single line.

* Redo the testing docs page

- Addresses another part of #1687
- Also, fix a few linter issues in the ospec binary

* Add note about third-party cookies, tweak a line

* Make the JSX comparison much more meaningful

And let the code speak for itself. Don't fuel the flame wars any more
than what they've already become. We should be *unopinionated*, and so
I've updated those docs to remove the existing opinion.

* Remove a bunch of outdated ES6 references

* Remove the CSS page

docs/hyperscript.md

@@ -438,7 +438,7 @@ m("ul", users.map(function(u) { // <ul>
 	                            //   <li>Mary</li>
 }))                             // </ul>
 
-// ES6:
+// ES6+:
 // m("ul", users.map(u =>
 //   m("li", u.name)
 // ))