changed import to function on UNIX as well

Author: joeri-vv

README.md

@@ -48,7 +48,7 @@ Get the package and it's dependencies:
 
 Run the example:
 
-`cd vendor\bitvavo\php-bitvavo-api\example`
+`cd vendor/bitvavo/php-bitvavo-api/example`
 
 `php example.php`
 

bitvavo.php

@@ -1,5 +1,5 @@
 <?php
-require __DIR__.'\..\..\..\vendor\autoload.php';
+require __DIR__.'/../../../vendor/autoload.php';
 use Ratchet\MessageComponentInterface;
 use Ratchet\ConnectionInterface;