added setConfig{,JSON} to ApiHelper to reduce redundant code
implemented setConfig{,JSON} for warehouse grouping
added ApiWarhouseGrouping::setConfig to api
use warehouseGrouping setConfig
fixed small bug: couldn't create group which name contained a hyphen
added change group functions
added change group functionality to api
added change group name functionality to webinterface
added delet functionality to warehousegrouping
added delete functionality to api
added delete functionality to webinterface
LAZY COMMIT, DELETE AFTER CLEANUP