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/Input/StringInput.php

@@ -28,8 +28,6 @@ class StringInput extends ArgvInput
     const REGEX_QUOTED_STRING = '(?:"([^"\\\\]*(?:\\\\.[^"\\\\]*)*)"|\'([^\'\\\\]*(?:\\\\.[^\'\\\\]*)*)\')';
 
     /**
-     * Constructor.
-     *
      * @param string $input An array of parameters from the CLI (in the argv format)
      */
     public function __construct($input)