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/myclabs/deep-copy/fixtures/f003/Foo.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace DeepCopy\f003;
+
+class Foo
+{
+    private $name;
+    private $prop;
+
+    public function __construct($name)
+    {
+        $this->name = $name;
+    }
+
+    public function getProp()
+    {
+        return $this->prop;
+    }
+
+    public function setProp($prop)
+    {
+        $this->prop = $prop;
+
+        return $this;
+    }
+}