added whie-black-listing, http counter is a histogram now

advanced-example.js

@@ -0,0 +1,28 @@
+"use strict";
+
+const express = require("express"),
+    app = express(),
+    promBundle = require("express-prom-bundle"),
+    promClient = require("prom-client");
+
+const bundle = promBundle({
+    prefix: "demo_app:something:",
+    blacklist: [/up/]
+});
+
+app.use(bundle);
+
+let c1 = new bundle.promClient.Counter("c1", "c1 help");
+c1.inc(10);
+
+let c2 = bundle.factory.newCounter("c2", "c2 help");
+c2.inc(20);
+
+app.get("/foo", (req, res) => {
+    setTimeout(() => {
+        res.send("foo response");
+    }, 500);
+});
+app.get("/bar", (req, res) => res.send("bar response"));
+
+app.listen(3001);