Set version to 1.6.
Fixes ambiguous method error message was displayed when deleting shipments for sales return.
Add debit and credit column.
Change income statements calculation.
Disable validation in sales returns.
Fixes transactions were not actually deleted but balance was updated.
Fixes wrong period dates in reports.
Remove periodic inspections for expiration because now they will be executed by daemon.
Fixes incorrect calculation when updating cache for accumulator (totals) and balance.
Disable eager loading for many to one relation in `Pesan`.