Parsing error for HTML entity in nested JSX.

The html entity in the following causes a `SyntaxError: Unexpected token ;`  in both current master and React 0.3.

```
/** @jsx React.DOM */
var mylist = ['a', 'b', 'c'];
// Fails with entity below
React.renderComponent(
    <p>
        {mylist.map(function (id) {
            return (<span>{id} &nbsp;</span>);
        })}
    </p>, document.body);
```

JSFiddle: http://jsfiddle.net/VLmQt/
