Add package.json for Basic example

This removes express as a dev dep.
Add package.json for Advanced example
Update signature to render(file, context, options)

This better mimics the underlying Handlebars rendering API by separating the `context` from the rendering `options`.
Switch to graceful-fs to support large #s of files

If there are a ton of partials that need to be loaded from disk, this could throw an `EMFILE` error; switching to `graceful-fs` can recover from those errors.