dillon1000/react

Consolidate ReactDOMNodeCache and getDOMNodeID into ReactID.

When we move away from using the "id" attribute to identify
React-generated elements, we will need the cache (formerly
ReactDOMNodeCache) to be tied much more closely to the code that looks
elements up by ID (getDOMNodeID) and sets element IDs, since the magic of
document.getElementById will no longer be available.

The priming functions are going to come in handy when we create new DOM
fragments in mountComponent.

For backwards compatibility, the ReactDOMNodeCache and getDOMNodeID
modules still exist, but they are implemented entirely in terms of
functions exported from ReactID.