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/finder/SplFileInfo.php

@@ -22,8 +22,6 @@ class SplFileInfo extends \SplFileInfo
     private $relativePathname;
 
     /**
-     * Constructor.
-     *
      * @param string $file             The file name
      * @param string $relativePath     The relative path
      * @param string $relativePathname The relative path name