[FEATURE] Option to disable multi-route rendering

- Added option to disable multi-route rendering by calling `Router::setRenderMultipleRoutes($bool)`.
- Added alias for easier access `SimpleRouter::enableMultiRouteRendering($bool)`.
- Added php-unit tests for multi-routing enabled and disabled.

tests/Pecee/SimpleRouter/RouterUrlTest.php

@@ -11,7 +11,7 @@ class RouterUrlTest extends \PHPUnit\Framework\TestCase
     {
         TestRouter::get('/', 'DummyController@method1');
         TestRouter::get('/page/{id?}', 'DummyController@method1');
-        TestRouter::get('/test-output', function() {
+        TestRouter::get('/test-output', function () {
             return 'return value';
         });
 
@@ -175,7 +175,7 @@ class RouterUrlTest extends \PHPUnit\Framework\TestCase
     {
         TestRouter::request()->setHost('google.com');
 
-        TestRouter::get('/admin/', function() {
+        TestRouter::get('/admin/', function () {
             return 'match';
         })->setMatch('/^\/admin\/?(.*)/i');
 
@@ -183,4 +183,42 @@ class RouterUrlTest extends \PHPUnit\Framework\TestCase
         $this->assertEquals('match', $output);
     }
 
+    public function testRenderMultipleRoutesDisabled()
+    {
+        TestRouter::router()->setRenderMultipleRoutes(false);
+
+        $result = false;
+
+        TestRouter::get('/', function () use (&$result) {
+            $result = true;
+        });
+
+        TestRouter::get('/', function () use (&$result) {
+            $result = false;
+        });
+
+        TestRouter::debug('/');
+
+        $this->assertTrue($result);
+    }
+
+    public function testRenderMultipleRoutesEnabled()
+    {
+        TestRouter::router()->setRenderMultipleRoutes(true);
+
+        $result = [];
+
+        TestRouter::get('/', function () use (&$result) {
+            $result[] = 'route1';
+        });
+
+        TestRouter::get('/', function () use (&$result) {
+            $result[] = 'route2';
+        });
+
+        TestRouter::debug('/');
+
+        $this->assertCount(2, $result);
+    }
+
 }