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/phpunit/phpunit-mock-objects/tests/ProxyObjectTest.php

@@ -1,6 +1,6 @@
 <?php
 /*
- * This file is part of the PHPUnit_MockObject package.
+ * This file is part of the phpunit-mock-objects package.
  *
  * (c) Sebastian Bergmann <sebastian@phpunit.de>
  *
@@ -8,7 +8,9 @@
  * file that was distributed with this source code.
  */
 
-class Framework_ProxyObjectTest extends PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class ProxyObjectTest extends TestCase
 {
     public function testMockedMethodIsProxiedToOriginalMethod()
     {