Add typescript typings file.

package.json

@@ -30,5 +30,6 @@
     "pretest": "npm run build",
     "test": "node_modules/.bin/mocha",
     "watch": "node_modules/.bin/coffee --watch --compile --output lib/ src/"
-  }
+  },
+  "typings": "src/index.d.ts"
 }

src/index.d.ts

@@ -0,0 +1,8 @@
+// This file describes the package to typescript.
+
+/**
+ * Returns the number of milliseconds since the page was loaded (if browser)
+ * or the node process was started.
+ */
+declare function now(): number;
+export = now;