Add client/server mention in componentDid/WillMount documentation
Fix docstring arg order in createDOMComponentClass
add `ReactComponentWithPureRenderMixin` to addons
Merge pull request #1309 from spicyj/dom-arg-order

Fix docstring arg order in createDOMComponentClass
Fix hasOwnProperty check typo in mixStaticSpecIntoComponent
Remove extraneous assert
Clean up assertions on descriptors

By making this fail, we catch a lot of tests that are expecting rendered
instances but are actually operating on descriptors.
Update CONTRIBUTING.md

Updating doc to point to the brand new CLA form at https://code.facebook.com/cla
First phase to true descriptors

This moves all convenience constructors to use frozen ReactDescriptors.
BeforeInputEventPlugin: Support Opera <= 12

Add support for Opera <= 12 (Presto) in `BeforeInputEventPlugin`.

It turns out that Opera 12 has a `TextEvent` in `window`, but doesn't actually fire any input events. Even `input` apparently doesn't fire. Fall back to keypress handling in this case.
Merge pull request #1310 from plievone/patch-1

Fix hasOwnProperty check typo in mixStaticSpecIntoComponent
[blog] The Road to 1.0
Fix spelling of 'existence'
Formatting

An extra "`" snuck in there.
Fix minor typo in `update` `$push` directive
Merge pull request #1320 from gasi/patch-2

Fix minor typo in `update` `$push` directive
Merge pull request #1318 from spicyj/existence

Fix spelling of 'existence'
Add optional harmony support to browser transform

This mirrors the react-tools API; it doesn't include support (yet) for transforming `<script type="text/jsx">` blocks with the ES6 transforms, mostly because I don't have a good API in mind there.

Test Plan:
Ran

    JSXTransformer.transform("var two = () => 2;", {harmony: true}).code

in Chrome's dev console and got back some ES5 code.
Merge pull request #1322 from spicyj/transformer-harmony

Add optional harmony support to browser transform
Merge pull request #1288 from vjeux/server_docs

Add client/server mention in componentDid/WillMount documentation