Composer integration and bugfixes

Hi your project is just what I was looking for, but I had to make some adjustments:

- composer now adds the commandline tool to vendor/bin
- commandline tool now includes vendor/autoload.php
- saveAs opens files in write mode.
- interfaces now support namespaces
- type hints work in namespaces
- interface metods are always public so I remoced the "public" modifier