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/console/Tests/Fixtures/FooLock2Command.php

@@ -0,0 +1,28 @@
+<?php
+
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Command\LockableTrait;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class FooLock2Command extends Command
+{
+    use LockableTrait;
+
+    protected function configure()
+    {
+        $this->setName('foo:lock2');
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        try {
+            $this->lock();
+            $this->lock();
+        } catch (LogicException $e) {
+            return 1;
+        }
+
+        return 2;
+    }
+}