New createdByClientName and splitOrigin values in the orders API

The Order and Check objects in the orders API now include a createdByClientName value, and the Check object also includes a splitOrigin value.

The createdByClientName value is the name of the client that created the order or check.

The splitOrigin value references the check that a given check was split from. This value returns null for checks that were not created through a split operation, and for the original check in a split.

Both values are read-only.