* add phpunit as a dev dependency

* add some basic tests for UrlHelper::rewrite_relative()
 * fix UrlHelper::rewrite_relative() to work better on non-absolute
   relative URL paths

vendor/nikic/php-parser/lib/PhpParser/Node/Expr/ConstFetch.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\Node\Expr;
+
+use PhpParser\Node\Expr;
+use PhpParser\Node\Name;
+
+class ConstFetch extends Expr
+{
+    /** @var Name Constant name */
+    public $name;
+
+    /**
+     * Constructs a const fetch node.
+     *
+     * @param Name  $name       Constant name
+     * @param array $attributes Additional attributes
+     */
+    public function __construct(Name $name, array $attributes = []) {
+        $this->attributes = $attributes;
+        $this->name = $name;
+    }
+
+    public function getSubNodeNames() : array {
+        return ['name'];
+    }
+    
+    public function getType() : string {
+        return 'Expr_ConstFetch';
+    }
+}