Fix 'Purchase is a donation' checkbox being overwritten by quick edit.
Fix 'Product will not be shipped to customer' setting being overwritten by quick edit.
Link 'Product will not be shipped to customer' label to checbox.
Fix product stock notifcation settings being overwritten by quick edit.
Merge pull request #1589 from benhuson/nonce_save_product_2

Nonce save product checkboxes