[!!!][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/ClassLoaderTest.php

@@ -0,0 +1,30 @@
+<?php
+
+require_once 'Dummy/DummyMiddleware.php';
+require_once 'Dummy/DummyController.php';
+require_once 'Dummy/ClassLoader/CustomClassLoader.php';
+
+class ClassLoaderTest extends \PHPUnit\Framework\TestCase
+{
+
+    public function testCustomClassLoader()
+    {
+        $result = false;
+
+        TestRouter::setCustomClassLoader(new CustomClassLoader());
+
+        TestRouter::get('/', 'NonExistingClass@method3');
+        TestRouter::get('/test-closure', function($status) use(&$result) {
+            $result = $status;
+        });
+
+        $classLoaderClass = TestRouter::debugOutput('/', 'get', false);
+        TestRouter::debugOutput('/test-closure');
+
+        $this->assertEquals('method3', $classLoaderClass);
+        $this->assertTrue($result);
+
+        TestRouter::router()->reset();
+    }
+
+}