lib: Remove TreeIterator

Nodes implementing the NodeInterface (which extends the RecursiveIterator interface)
are already iterable.

library/Icinga/Data/Tree/TreeIterator.php

@@ -1,90 +0,0 @@
-<?php
-// {{{ICINGA_LICENSE_HEADER}}}
-// {{{ICINGA_LICENSE_HEADER}}}
-
-namespace Icinga\Data\Tree;
-
-//use RecursiveIterator;
-//
-//class TreeIterator implements RecursiveIterator
-//{
-//    protected $position = 0;
-//
-//    protected $nodes;
-//
-//    public function __construct(NodeInterface $node)
-//    {
-//        $this->nodes = $node->getChildren();
-//    }
-//
-//    public function hasChildren()
-//    {
-//        return $this->current()->hasChildren();
-//    }
-//
-//    public function getChildren()
-//    {
-//        return new self($this->current());
-//    }
-//
-//    public function current()
-//    {
-//        return $this->nodes[$this->position];
-//    }
-//
-//    public function next()
-//    {
-//        ++$this->position;
-//    }
-//
-//    public function valid()
-//    {
-//        return isset($this->nodes[$this->position]);
-//    }
-//
-//    public function rewind()
-//    {
-//        $this->position = 0;
-//    }
-//
-//    public function key()
-//    {
-//        return $this->position;
-//    }
-//}
-
-use ArrayIterator;
-use RecursiveIterator;
-
-class TreeIterator extends ArrayIterator implements RecursiveIterator
-{
-    /**
-     * Create a new TreeIterator
-     *
-     * @param NodeInterface $node
-     */
-    public function __construct(NodeInterface $node)
-    {
-        parent::__construct($node->getChildren());
-    }
-
-    /**
-     * Whether an iterator can be created for the current node
-     *
-     * @return bool
-     */
-    public function hasChildren()
-    {
-        return $this->current()->hasChildren();
-    }
-
-    /**
-     * Return an iterator for the current node
-     *
-     * @return self
-     */
-    public function getChildren()
-    {
-        return new self($this->current());
-    }
-}