Add definitions for gulp-csso (https://github.com/ben-eb/gulp-csso)

gulp-csso/gulp-csso-tests.ts

@@ -0,0 +1,14 @@
+/// <reference path="gulp-csso.d.ts" />
+/// <reference path="../gulp/gulp.d.ts" />
+
+import gulp = require('gulp');
+import csso = require('gulp-csso');
+
+gulp.task('default', () =>
+    gulp.src('./main.css')
+        .pipe(csso())
+        .pipe(gulp.dest('./out'))
+);
+
+csso(true);
+csso(false);

gulp-csso/gulp-csso.d.ts

@@ -0,0 +1,12 @@
+// Type definitions for gulp-csso v1.0.0
+// Project: https://github.com/ben-eb/gulp-csso
+// Definitions by: Tanguy Krotoff <https://github.com/tkrotoff>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../node/node.d.ts" />
+
+declare module 'gulp-csso' {
+    function csso(structureMinimization?: boolean): NodeJS.ReadWriteStream;
+
+    export = csso;
+}