Updated Grunt configuration file

Removed Grunt's cssmin plugin from Grunt watch, so it won't minify every
time the CSS file changes, and will only minify when 'grunt' is run.
Cosmetic Sass changes, updated styles

Replaced constants with variables and updated styles.
Imported fonts correctly
Auto-generated files
Cleaned up index.html, changed stylesheet reference

Removed unnecessary <div>s from index.html, fixed body copy, and changed
stylesheet reference to css/unmin.css instead of css/min.css (while in
development).