Billingo + Heartland Integration

Keep Billingo and Heartland aligned: when finance events happen in one, update the other automatically.

Example: when Billingo's "Watch Bank Accounts" fires, WEXTL can "Add Item to a Purchase Order" in Heartland. Billingo has 12 triggers (including Watch Bank Accounts, Watch Bank Accounts, and Watch Clients); Heartland has 50 actions (including Add Item to a Purchase Order, Add Item to a Receipt, and Add Item to a Return).