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.