Updates and clean-up

.htaccess - Updated to v1.1.0.
_defaults.scss - Updated and added more from HTML5 Boilerplate.
_helpers.scss - Updated variables and added back prefixer mixin.
_normalize.scss - Changed back to v1.1.3.
_variables.scss - Update variables and comments.
website.json - Include .htaccess in build by default.
package.json - Updated devDependencies.