Tie MultiChild queue to ReactReconcileTransaction

Fixes #1147.

This now forces all DOM operations for a subtree to be applied when the calling `setState` or `React.renderComponent` call returns (when updates aren't being batched). This means that we can't batch innerHTML setting across different component hierarchies, but our strategy for doing so before seems flawed. It could be possible to make the old way work but it would require making setState always async even when batching isn't in play and refactoring DOMChildrenOperations to not be confused by multiple updates to the same node.