Add pear modules, mail and net_smtp via composer (#93)

Add pear modules, mail and net_smtp via composer, remove php 5.6 build due to phpunit 6

lib/composer/vendor/symfony/debug/Tests/Fixtures/FinalMethod.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class FinalMethod
+{
+    /**
+     * @final since version 3.3.
+     */
+    public function finalMethod()
+    {
+    }
+
+    public function anotherMethod()
+    {
+    }
+}