Don't ignore source files

Hello !

A few questions here: 
I'm planning on building a yeoman generator based on the [webapp](https://github.com/yeoman/generator-webapp) one but with groundwork vs [bootstrap for sass](https://github.com/jlong/sass-bootstrap) choice and with [assemble](https://github.com/assemble/assemble) backed in for easy templating.

1.    Is that ok with you if I make that generator and release it on github and npm ?

2.    I plan on using this generator for some work I have, and I'd rather use groundwork's source files  than the compiled version. It's mainly to be able to use your mixins in my own SCSS files. That's the purpose of this pull request: allow the source files to come with `bower install` and therefore permit the more fine tuned usage of groundwork's features without installing it by hand, dropping scss files here and images there every time.

3.    One last thing I would like to hear your thoughts on is the possibility to have one file only that would be responsible for the partials' imports. The reason I ask is : based on the previous proposition, it would make sense to not have to modify groundworks files at all but still be able to configure it. The `_settings.scss` was already a good step forward to help with that since we should be able to copy it's content in our own `main.scss` provided that `_settings.scss` uses the `!default` keyword it would get overridden. It would be a similar mechanism with this new file.

Are these things of interest to you or not at all ?