Include sass source in build

[nathanstitt]

This enables projects that already use scss to import the source files into their builds and to customize the variables.

I did not update the README to mention this but can if you'd like

I also fixed a import issue that I hit when trying to import them.

After building the dist directory will contain:

dist
├── _render.scss
├── base
│   ├── _animation.scss
│   ├── _bs.scss
│   ├── _icons.scss
│   ├── _mixins.scss
│   ├── _rtl.scss
│   ├── _variables.scss
│   └── rtl
│       ├── _bs.scss
│       ├── _controls.scss
│       ├── _group-actions.scss
│       ├── _mixins.scss
│       ├── _row.scss
│       └── _stage.scss
├── components
│   ├── _autocomplete.scss
│   ├── _column.scss
│   ├── _controls.scss
│   ├── _field-edit.scss
│   ├── _field.scss
│   ├── _group-actions.scss
│   ├── _panels.scss
│   ├── _row-edit.scss
│   ├── _row.scss
│   ├── _stage.scss
│   └── component.scss
├── formeo.min.css
├── formeo.min.js
├── formeo.min.js.gz
└── formeo.scss