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
TodoMVC Flux Example
added dx and dy for laying out text with relative offsets
add `ReactComponentWithPureRenderMixin` to addons
Support `ms` vendor prefix when generating markup
Make EventPluginUtils clear dispatchIDs and dispatchListeners

The other dispatch utils clear these out and I found a bug where they weren't being cleared out.
I'm thinking this should probably be done in the `SyntheticEvent` constructor but at least this way it's consistent. Also, I know no one else uses `executeDispatchesInOrderStopAtTrue` except the `ResponderEventPlugin`.
Add scrolling attribute for <iframe>
Remove leftovers from ReactTransitionGroup rewrite

Looks like while rewriting @petehunt forgot to remove this block.
See: 9ac27cb551b85293d03d334363acd7cf9c77813a
This block used to contain the only `runNextTick` ocurrences in the whole project.
No tests broken after removal, no documentation affected.
Merge branch 'master' of github.com:facebook/react
[Docs][Tips] Entry on this.props.children and tweak component ref entry

Component ref entry wasn't registered in nav_tips.
Merge pull request #1329 from irae/transition-group-leftovers

Remove leftovers from ReactTransitionGroup rewrite
[docs] Amend "References to components" tip to mention descriptors.
Simplify comment.
Remove erroneous line about static methods.
Merge pull request #1345 from kmeht/referenceDoc

[docs] Amend "References to components" tip to mention descriptors.
Merge pull request #1308 from chenglou/pure

add `ReactComponentWithPureRenderMixin` to addons
Remove toJSON

This was temporarily needed since clone on mount introduced a cyclic reference
in __DEV__. This reverts that change since we now have descriptors.

To avoid a problem where toJSON may collide.