add a stand alone PSR-4 spec loader

Autoloader.php

@@ -0,0 +1,41 @@
+<?php
+/**
+ * A simple PSR-4 spec auto loader to allow json-machine to function the same as if it were loaded via Composer
+ *
+ * To use this just include this file in your script and the JsonMachine namespace will be made available
+ *
+ * i.e. require_once('/path/to/json-machine/Autoloader.php');
+ *
+ * See: https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-4-autoloader-examples.md
+ *
+ * @param string $class The fully-qualified class name.
+ * @return void
+ */
+spl_autoload_register(function ($class) {
+
+    // project-specific namespace prefix
+    $prefix = 'JsonMachine\\';
+
+    // base directory for the namespace prefix
+    $base_dir = __DIR__ . DIRECTORY_SEPARATOR . 'src' . DIRECTORY_SEPARATOR;
+
+    // does the class use the namespace prefix?
+    $len = strlen($prefix);
+    if (strncmp($prefix, $class, $len) !== 0) {
+        // no, move to the next registered autoloader
+        return;
+    }
+
+    // get the relative class name
+    $relative_class = substr($class, $len);
+
+    // replace the namespace prefix with the base directory, replace namespace
+    // separators with directory separators in the relative class name, append
+    // with .php
+    $file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';
+
+    // if the file exists, require it
+    if (file_exists($file)) {
+        require $file;
+    }
+});

README.md

@@ -543,14 +543,16 @@ json string at a time and then parse that using `Items::fromString()`... If even
 there's probably no solution yet via JSON Machine. A feature is planned which will enable you to iterate
 any structure fully recursively and strings will be served as streams.
 
-
 <a name="installation"></a>
 ## Installation
 ```bash
 composer require halaxa/json-machine
 ```
-or clone or download this repository (not recommended because of no autoloading).
-
+or clone or download this repository and add the following to your bootstrap file:
+```
+require_once('/path/to/json-machine/Autoloader.php');
+```
+The Autoloader.php file provides the same auto loading functionality as the Composer install.
 
 <a name="development"></a>
 ## Development