Add basic type definitions for express 4.x

compression/compression-tests.ts

@@ -0,0 +1,10 @@
+/// <reference path="compression.d.ts" />
+
+import express = require('express');
+import compress = require('compression');
+
+var app = express();
+app.use(compress());
+app.use(compress({
+    threshold: 512
+}));