Update NPM dependencies and switch to lib-sass

[cferdinandi]

package.json

"gulp": "^3.9.0",
"node-fs": "^0.1.7",
"del": "^1.2.0",
"lazypipe": "^0.2.4",
"gulp-plumber": "^1.0.1",
"gulp-flatten": "^0.0.4",
"gulp-tap": "^0.1.3",
"gulp-rename": "^1.2.2",
"gulp-header": "^1.2.2",
"gulp-footer": "^1.0.5",
"gulp-watch": "^4.2.4",
"gulp-livereload": "^3.8.0",
"gulp-jshint": "^1.11.1",
"jshint-stylish": "^2.0.1",
"gulp-concat": "^2.6.0",
"gulp-uglify": "^1.2.0",
"karma": "^0.12.37",
"gulp-karma": "^0.0.4",
"karma-coverage": "^0.4.2",
"jasmine": "^2.3.1",
"karma-jasmine": "^0.3.6",
"karma-phantomjs-launcher": "^0.2.0",
"karma-spec-reporter": "^0.0.19",
"karma-htmlfile-reporter": "^0.2.1",
"gulp-sass": "^2.0.3",
"gulp-minify-css": "^1.2.0",
"gulp-autoprefixer": "^2.3.1",
"gulp-svgmin": "^1.1.2",
"gulp-svgstore": "^5.0.2",
"gulp-markdown": "^1.0.0",
"gulp-file-include": "^0.11.1"

gulpfile.js

.pipe(sass({
    outputStyle: 'expanded',
    sourceComments: true
}))