+//
+// Returns all allocatable purchase transactions including all settled with selected payment.
+//
+// 1. not fully settled; supplier_id!=0, trans_no/type!=null (for trans edition)
+// 2. for given transaction; supplier_id=null, trans_no/type!=null (for transaction view)
+// 3. for supplier, not fully settled supplier_id!=0, trans_no/type=null (non fully settled documents for supplier exists)
+// 4. for all suppliers, not fully settled supplier_id==0, trans_no/type=null (any non fully settled documents exists)