Replace existing autoloader with Composer-supplied

- Move Friendica namespace to `src`
- Move required `ezyang/htmlpurifier` to vendor
- Remove existing static autoloader
- Change boot.php reference to the autoloader

vendor/ezyang/htmlpurifier/library/HTMLPurifier/Node/Text.php

@@ -0,0 +1,54 @@
+<?php
+
+/**
+ * Concrete text token class.
+ *
+ * Text tokens comprise of regular parsed character data (PCDATA) and raw
+ * character data (from the CDATA sections). Internally, their
+ * data is parsed with all entities expanded. Surprisingly, the text token
+ * does have a "tag name" called #PCDATA, which is how the DTD represents it
+ * in permissible child nodes.
+ */
+class HTMLPurifier_Node_Text extends HTMLPurifier_Node
+{
+
+    /**
+     * PCDATA tag name compatible with DTD, see
+     * HTMLPurifier_ChildDef_Custom for details.
+     * @type string
+     */
+    public $name = '#PCDATA';
+
+    /**
+     * @type string
+     */
+    public $data;
+    /**< Parsed character data of text. */
+
+    /**
+     * @type bool
+     */
+    public $is_whitespace;
+
+    /**< Bool indicating if node is whitespace. */
+
+    /**
+     * Constructor, accepts data and determines if it is whitespace.
+     * @param string $data String parsed character data.
+     * @param int $line
+     * @param int $col
+     */
+    public function __construct($data, $is_whitespace, $line = null, $col = null)
+    {
+        $this->data = $data;
+        $this->is_whitespace = $is_whitespace;
+        $this->line = $line;
+        $this->col = $col;
+    }
+
+    public function toTokenPair() {
+        return array(new HTMLPurifier_Token_Text($this->data, $this->line, $this->col), null);
+    }
+}
+
+// vim: et sw=4 sts=4