Added Debug and JSON Stream loaders

Author: gplanchat

src/Loader/DebugLoader.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace Kiboko\Component\Pipeline\Loader;
+
+final class DebugLoader extends StreamLoader
+{
+    protected function formatLine($line)
+    {
+        return var_export($line, true) . PHP_EOL;
+    }
+}

src/Loader/JSONStreamLoader.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace Kiboko\Component\Pipeline\Loader;
+
+final class JSONStreamLoader extends StreamLoader
+{
+    protected function formatLine($line)
+    {
+        return \json_encode($line);
+    }
+}