feat: Поддержка psr4. Кеширование шаблона

examples/example.php

@@ -1,14 +1,16 @@
 <?php
 
-require_once '../Klein.php';
+require_once '../src/Klein.php';
+
+use ctiso\Klein;
 
 function title($x) {
     return ucfirst($x);
 }
 
-$tpl = new Klein('tempalte.html');
+$tpl = new Klein(__DIR__ . '/cache');
 
-echo $tpl->render([
+echo $tpl->render('template.html', [
     'pagename' => 'awesome people',
     'authors' => [['name' => 'Paul', 'age' => 10], ['name' => 'Jim', 'age' => 11], ['name' => 'Jane', 'age' => 12]],
     'city'=> [