implement plugin routing masks, add example plugin

plugins/example_routing/example_routing.php

@@ -0,0 +1,46 @@
+<?php
+class Example_Routing extends Plugin implements IHandler {
+
+	// Demonstrates adding a custom handler and method:
+	// backend.php?op=test&method=example
+	// and masking a system builtin public method:
+	// public.php?op=getUnread
+
+	// Plugin class must implelement IHandler interface and has
+	// a public method of same name as being registered.
+	//
+	// Any system method may be masked by plugins.
+
+	private $link;
+	private $host;
+
+	function __construct($host) {
+		$this->link = $host->get_link();
+		$this->host = $host;
+
+		$host->add_handler("test", "example", $this);
+		$host->add_handler("public", "getunread", $this);
+	}
+
+	function getunread() {
+		print rand(0,100); # yeah right
+	}
+
+	function example() {
+		print "example method called";
+	}
+
+	function csrf_ignore($method) {
+		return true;
+	}
+
+	function before($method) {
+		return true;
+	}
+
+	function after() {
+		return true;
+	}
+
+}
+?>