not compatible with PHP Version 5.6 / Oxid EE 5.6

[nu-fp]

Hello,
I'm currently testing out this Oxid module and it is not working on Oxid EE 5.3 and PHP 5.6. Some code parts are not supported by PHP 5.6, eg. wle/Wallee/Core/WalleeModule.php line 549 in Version 1.0.47. This was changed in 1.0.41.
And some classes are from newer Oxid versions are used, eg. use OxidEsales\EshopCommunity\Core\ShopVersion in wle/Wallee/Core/WalleeModule.php.
Kind regards