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

test/TestTemplate.php

@@ -1,4 +1,8 @@
 <?php
+class PHPUnit_Framework_TestCase extends \PHPUnit\Framework\TestCase{
+
+}
+
 class TestTemplate extends PHPUnit_Framework_TestCase
 {