fix gulpfile

gulpfile.js

@@ -6,7 +6,7 @@ const browserify	= require( 'browserify' );
 const babelify		= require( 'babelify' );
 const buffer		= require( 'vinyl-buffer' );
 const sourcemaps	= require( 'gulp-sourcemaps' );
-const sass			= require( 'gulp-sass' );
+const sass			= require( 'gulp-sass' )( require('sass') );
 const source		= require( 'vinyl-source-stream' );
 const uglify		= require( 'gulp-uglify' );
 const es			= require( 'event-stream' );