Add ignore folders

I am building an [AngularJS application](https://github.com/scottnath/atlas) and my file structure is being set up differently to follow [Google's recommended file/folder structure](https://docs.google.com/a/scottnath.com/document/d/1XXMvReO8-Awi1EZXAXS4PzDzdNvV6pGcuaF4Q9821Es/pub). This has led me to put my main .scss file inside a folder, which is next to all my other component folders ([folder structure here](https://github.com/scottnath/atlas/tree/master/app).) Therefore, just choosing to add ```@import '../**/*.scss'``` will also include the main styles.scss file, which then causes a compass compilation error.

Anyway, I've added functionality to your script which allows a user to choose folders which it wants css-globbing to ignore.

Hope this helps! Glad to make changes if needed.

-Scott