[FEATURE] switch to cleancss instead of minifycss

gulpfile.js/tasks/build.js

@@ -15,7 +15,7 @@ var filter = require('gulp-filter');
 var ngAnnotate = require('gulp-ng-annotate');
 var useref = require('gulp-useref');
 var uglify = require('gulp-uglify');
-var minifyCss = require('gulp-minify-css');
+var cleanCSS = require('gulp-clean-css');
 var minifyHtml = require('gulp-minify-html');
 var preprocess = require('gulp-preprocess');
 var gzip = require('gulp-gzip');
@@ -68,7 +68,7 @@ function compile(callback) {
     .pipe(uglify())
     .pipe(jsFilter.restore())
     .pipe(cssFilter)
-    .pipe(minifyCss())
+    .pipe(cleanCSS())
     .pipe(cssFilter.restore())
     .pipe(assets.restore())
     .pipe(useref())

package.json

@@ -37,6 +37,7 @@
     "gulp-babel": "^6.1.2",
     "gulp-bump": "^1.0.0",
     "gulp-changed": "^1.3.0",
+    "gulp-clean-css": "^2.0.11",
     "gulp-cloudfront": "0.0.14",
     "gulp-coffee": "~2.3.1",
     "gulp-combine-mq": "^0.4.0",
@@ -48,7 +49,6 @@
     "gulp-if": "^2.0.0",
     "gulp-imagemin": "^2.4.0",
     "gulp-inject": "^3.0.0",
-    "gulp-minify-css": "^1.2.3",
     "gulp-minify-html": "^1.0.5",
     "gulp-ng-annotate": "~1.0.0",
     "gulp-ng-config": "^1.2.1",