Add a compatibility shim.

contracts/PreICOProxyBuyer_EventCompatibility.sol

@@ -0,0 +1,19 @@
+/**
+ * This smart contract code is Copyright 2017 TokenMarket Ltd. For more information see https://tokenmarket.net
+ *
+ * Licensed under the Apache License, version 2.0: https://github.com/TokenMarketNet/ico/blob/master/LICENSE.txt
+ */
+
+pragma solidity ^0.4.6;
+
+/**
+ * ABI compatibility shim to get.
+ *
+ * You can use this shim to get events out of old PreICOProxyBuyer contracts.
+ */
+contract PreICOProxyBuyer_EventCompatibility {
+
+  /** Somebody loaded their investment money */
+  event Invested(address investor, uint weiAmount, uint128 customerId);
+
+}