Add a SplitPullPayment contract that combines distribution of funds and delayed withdrawal from each party

test/helpers/SplitPullPaymentMock.sol

@@ -0,0 +1,9 @@
+pragma solidity ^0.4.15;
+
+import '../../contracts/payment/SplitPullPayment.sol';
+
+// mock class using SplitPullPaymentMock
+contract SplitPullPaymentMock is SplitPullPayment {
+  function SplitPullPaymentMock() SplitPayment(0) payable { }
+  function () payable {}
+}