switched from grunt to gulp

gulp/clean.js

@@ -0,0 +1,9 @@
+var gulp = require('gulp');
+var clean = require('gulp-clean');
+
+var paths = require('./paths');
+
+gulp.task('clean', function () {
+    return gulp.src(paths.dest.root, {read: false})
+        .pipe(clean());
+});