rework class system to use subdirectories

add placeholder plugin/hook system

classes/plugin/example.php

@@ -0,0 +1,11 @@
+<?
+	class Plugin_Example extends Plugin {
+		function initialize() {
+			$this->add_listener('article_before');
+		}
+
+		function article_before(&$line) {
+			$line["title"] = "EXAMPLE/REPLACED:" . $line["title"];
+		}
+	}
+?>