Added SASS to project

- Added SASS dependency to file
- Grunt now auto-compiles SASS files on save
EDIT** - added .sass-cache folder to .gitignore file and also removed it from the repo

Note:
Sass is dependent on being installed through a ruby gem. Grunt, nor NPM, will install it automatically for you. Before relaunching Grunt, do the following:

1. gem install sass 
2. npm install