Added PSR4 autoload function for the project.

src/autoload.php

@@ -0,0 +1,44 @@
+<?php 
+
+/* ----------------------------------------------------------------------------
+ * Easy!Appointments - Open Source Web Scheduler
+ *
+ * @package     EasyAppointments
+ * @author      A.Tselegidis <alextselegidis@gmail.com>
+ * @copyright   Copyright (c) 2013 - 2016, Alex Tselegidis
+ * @license     http://opensource.org/licenses/GPL-3.0 - GPLv3
+ * @link        http://easyappointments.org
+ * @since       v1.2.0
+ * ---------------------------------------------------------------------------- */
+
+function register($namespace, $path) { 
+    spl_autoload_register(function ($class) {
+        // project-specific namespace prefix
+        $prefix = 'EA\\' . $namespace . '\\';
+
+        // base directory for the namespace prefix
+        $base_dir = __DIR__ . '/' . $path;
+
+        // 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;
+        }
+    });
+}
+
+register('Engine', __DIR__ . '/engine'); 

src/index.php

@@ -49,6 +49,18 @@
 
  require_once __DIR__ . '/config.php';
 
+ /*
+  *---------------------------------------------------------------
+  * EASY!APPOINTMENTS AUTOLOAD FILE
+  *---------------------------------------------------------------
+  *
+  * Include Easy!Appointments autoload file so that namespace 
+  * classes are loaded automatically.
+  *
+  */
+
+ require_once __DIR__ . '/autoload.php';
+
 
  /*
   *---------------------------------------------------------------