Version 2.1.0

Hi Prestashop Team,

here is the latest Version for the module.
New Features:
- Refund within the Prestashop administration(Orderdetails)
- Preauthorization / Capture
 * Create a preauth instead of an Transaction and charge the customer later(Orderdetails)
- Added compatibility to EU-Legal module
- Added Upgrade script

best regards,
Stefan
```$db_result = Configuration::get('PS_OS_REFUND');``` should return the same  value;