SCSS variables from imported modules don't resolve

Here's a question / possible feature request for projects with node packages, such as those using Webpack and `sass-loader`.

If I have a file like this in my project dir:

```scss
// _variables.scss
$coolcolor: $f00;
```

Pigments will read it and highlight `$coolcolor` in red as expected throughout my project, even if I haven't opened the file in Atom. (This is great)

However, if I bring in some variables form a package in `node_modules`:

```scss
// _variables.scss
@import "~bulma/sass/utilities/_all";

$coolcolor: $f00;
```
The bulma import in the example above brings in variables like `$primary` and `$secondary`, but those won't be highlighted by Pigments.

Maybe this is the intended behavior, because `node_modules/*` is in the "Ignored Names" section in the Pigment options, but I have explicitly imported the file into my project, so I might expect Pigments to read that file. Is there a way to do this without just whitelisting all of `node_modules/`?

Examine a lógica de resolução de arquivos no pacote pigments, provavelmente em lib/pigments.coffee ou em um arquivo semelhante. Entenda como os caminhos ignorados (como node_modules) são tratados. O issue exige modificar a resolução de imports para analisar arquivos SCSS importados mesmo que estejam dentro de node_modules, mas somente quando forem importados explicitamente. Verifique os pontos de integração do sass-loader e do Webpack. Faça um teste criando um projeto de exemplo com bulma e verificando o realce de variáveis após as alterações.

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