prettyPrint renders HTML entities in JSX

When pretty printing JSX with HTML entities, the entities are rendered as their display character instead of the source.

`print` works as expected -

``` javascript
recast.print(recast.parse('<'));
// <'
```

`prettyPrint` breaks the output -

``` javascript
recast.prettyPrint(recast.parse('<'));
// '<;'
```

We are using recast to make AST transforms and convert back to code using prettyPrint. Having `lt;` transformed to `<` breaks the subsequent JSX parsing.

Reproduce the issue with the provided recast.parse, print, and prettyPrint JSX examples, then start at the prettyPrint entry point and trace how the HTML entity is handled. Done means prettyPrint preserves the source entity so the generated JSX can be parsed again without changing it to its display character.

Written by the indexing model from the issue text.