Fix handling of relative paths in the `importFile` function (#449)
Fix handling of relative paths in the `importFile` function (#449)

- This was originally implemented incorrectly in #264.
- A later call to `Twig.path.parsePath` in the `render` function would properly load the correct file after `importFile` failed to do so, but not before an error would be thrown.
twigjs/twig.js,twigjs/twig.js,justjohn/twig.js,twigjs/twig.js,justjohn/twig.js,justjohn/twig.js