Add support for directory aliases

[necolas]

Use case I have is wanting to alias part of a path (a la requirejs config).

--some/long/path
  --one
    --index.css
  --two
   --index.css

--some/other/path
  --text
    --index.css

use(reworkNPM({
  alias: {
    "components": "some/long/path"
    "utils": "some/other/path"
  }
});

@import "utils/text";
@import "components/one";
@import "components/two";

[conradz]

Fixed in 0665e94. The alias option is now applied to directories of imported files, and is never used for relative imports.

[necolas]

Thanks!