Polyfill and normalize HTML5 "key", deprecates which and keyCode
Nodes that have had their child removed already, but then get given a new one no longer bug-out.

In the case of having an animated node which is, after the leave-transition has been activated, then re-added in a render call causes React to 'break'.  This is especially noticeable if you spam to removal and re-addition of an item in a ReactTransitionGroup.

This fix simply stops the leave transition and restarts the enter transition.
Updated the animation-fix to account for transitionEnter being false.
Fix scrollLeft/scrollTop warning in latest Chrome

Chrome gives the warnings

```
body.scrollLeft is deprecated in strict mode. Please use 'documentElement.scrollLeft' if in strict mode and 'body.scrollLeft' only if in quirks mode.
body.scrollTop is deprecated in strict mode. Please use 'documentElement.scrollTop' if in strict mode and 'body.scrollTop' only if in quirks mode.
```

the first time getUnboundedScrollPosition is invoked. This fixes it. (All modern browsers support `pageYOffset`; IE 8 doesn't but works properly with `document.documentElement.scrollTop` except in quirks mode which React doesn't support.)
Community Round-up #14
Fix "Dynamic Children" example
Use feature detection and more robust recovering of whitespace for innerHTML in IE8
Community Round-up #12
Merge pull request #686 from vjeux/community_12

Community Round-up #12
Fix html-jsx compiler

It changed React Playground to add a required props but unfortunately didn't update the call sites of the front-page. I don't think it should be required so I'm just making it optional and providing the correct default value.

Test Plan:
 - Open the front page and make sure examples are working
 - Open /react/jsx-compiler.html and make sure it is working
 - Open /react/html-jsx.html and make sure it is working
Merge pull request #698 from vjeux/fix_compiler

Fix html-jsx compiler
typo
Merge pull request #699 from vjeux/fix_typo

typo
Merge pull request #684 from syranide/ie8dangerousinnerhtml

Use feature detection and more robust recovering of whitespace for innerHTML in IE8.
Merge pull request #607 from syranide/html5key

Polyfill and normalize HTML5 "key", deprecates which and keyCode
Merge pull request #642 from Cartas/master

ReactTransitionGroup can handle components being re-added before 'leave' transition has completed.
Note about react's version on the talk, since somethings have already changed since then
Removed unnecessary cleanup in isEventSupported
Adding note about onScroll on IE8
updating text as suggested by @petehunt