Remove custom attrs properly when setting to null

I don't think this particular codepath was exercised at all (because all the callers call deleteValueForProperty) but this fixes a bug here nonetheless.
Normalize whitespace for transformed JSX code
Update jasmine-support.js

fix typo in multiple error messages.
[addons] Renamed update() directives to commands
Add client/server mention in componentDid/WillMount documentation
TodoMVC Flux Example
added dx and dy for laying out text with relative offsets
add `ReactComponentWithPureRenderMixin` to addons
Fix hasOwnProperty check typo in mixStaticSpecIntoComponent
Support `ms` vendor prefix when generating markup
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'