[!!!][FEATURE] Removed php-di as suggested by #477

NOTE: Custom class-loader should be used to create custom integrations with frameworks like php-di. See documentation for more information.

- Removed all references to php-cli from composer + code.
- Added ClassLoader php-unit tests.

tests/Pecee/SimpleRouter/Dummy/ClassLoader/CustomClassLoader.php

@@ -0,0 +1,14 @@
+<?php
+
+class CustomClassLoader implements \Pecee\SimpleRouter\ClassLoader\IClassLoader
+{
+    public function loadClass(string $class)
+    {
+        return new DummyController();
+    }
+
+    public function loadClosure(callable $closure, array $parameters)
+    {
+        return \call_user_func_array($closure, ['result' => true]);
+    }
+}

tests/Pecee/SimpleRouter/Dummy/DummyController.php

@@ -16,6 +16,11 @@ class DummyController
     public function method2()
     {
 
+    }
+
+    public function method3()
+    {
+        return 'method3';
     }
 
 	public function param($params = null)