ProductGroup.php: added comments, improved ProductsPerPage, removed requireDefaultRecords and moved it to /code/data/
ProductGroup.php: added comments, improved ProductsPerPage, removed requireDefaultRecords and moved it to /code/data/

hpeide/silverstripe-shop,StephenHonor/silverstripe-shop,bummzack/silverstripe-shop,burnbright/silverstripe-shop,burnbright/silverstripe-shop,markguinn/silverstripe-shop,bummzack/silverstripe-shop,hailwood/silverstripe-shop,hailwood/silverstripe-shop,mediabeastnz/silverstripe-shop,markguinn/silverstripe-shop,mediabeastnz/silverstripe-shop,StephenHonor/silverstripe-shop,hailwood/silverstripe-shop,webtorque7/silverstripe-shop,burnbright/silverstripe-shop,StephenHonor/silverstripe-shop,silvershop/silvershop-core,webtorque7/silverstripe-shop,webtorque7/silverstripe-shop,mediabeastnz/silverstripe-shop,markguinn/silverstripe-shop,bummzack/silverstripe-shop