replace gulp-css-minify with gulp-clean-css to support NodeJS 6

.travis.yml

@@ -3,8 +3,8 @@ sudo: false
 language: node_js
 
 node_js:
-  - "0.12"
   - "4"
+  - "6"
 
 env:
   global:

gulpfile.js

@@ -243,7 +243,11 @@ gulp.task('build:less', function() {
     .pipe($.size({showFiles: true, title: 'source'}))
     // Disable advanced optimizations - selector & property merging, etc.
     // for Issue #19 https://github.com/allmobilize/amazeui/issues/19
-    .pipe($.minifyCss({noAdvanced: true}))
+    .pipe($.cleanCss({
+      advanced: false,
+      // @see https://github.com/jakubpawlowicz/clean-css#how-to-set-a-compatibility-mode
+      compatibility: 'ie8'
+    }))
     .pipe($.rename({
       suffix: '.min',
       extname: '.css'

package.json

@@ -40,20 +40,20 @@
   },
   "devDependencies": {
     "bistre": "^1.0.1",
-    "body-parser": "^1.14.1",
+    "body-parser": "^1.15.1",
     "cookie-parser": "^1.4.0",
     "debug": "^2.2.0",
     "del": "^2.1.0",
     "errorhandler": "^1.3.6",
     "express": "^4.13.3",
     "gulp": "^3.9.1",
     "gulp-autoprefixer": "^3.1.0",
+    "gulp-clean-css": "^2.0.7",
     "gulp-concat": "^2.6.0",
-    "gulp-header": "^1.7.1",
-    "gulp-less": "^3.0.5",
+    "gulp-header": "^1.8.2",
+    "gulp-less": "^3.1.0",
     "gulp-load-plugins": "^1.2.2",
-    "gulp-minify-css": "^1.2.1",
-    "gulp-nodemon": "^2.0.4",
+    "gulp-nodemon": "^2.0.7",
     "gulp-plumber": "^1.0.1",
     "gulp-rename": "^1.2.2",
     "gulp-replace": "^0.5.4",
@@ -64,9 +64,9 @@
     "handlebars": "^4.0.5",
     "hbs": "^4.0.0",
     "less-middleware": "^2.0.1",
-    "lodash": "^4.11.1",
+    "lodash": "^4.12.0",
     "morgan": "^1.6.1",
-    "run-sequence": "^1.1.5",
+    "run-sequence": "^1.2.0",
     "webpack-stream": "^3.2.0"
   },
   "license": "MIT"

tools/tasks/customizer.js

@@ -116,7 +116,10 @@ gulp.task('customizer:less', function() {
     }))
     .pipe(gulp.dest(cstmzPath))
     .pipe($.size({showFiles: true, title: 'source'}))
-    .pipe($.minifyCss({noAdvanced: true}))
+    .pipe($.cleanCss({
+      advanced: false,
+      compatibility: 'ie8'
+    }))
     .pipe($.rename({
       suffix: '.min',
       extname: '.css'