Add SB Curated (copied from the smartbugs repository).

dataset/unchecked_low_level_calls/mishandled.sol

@@ -0,0 +1,16 @@
+/*
+ * @source: https://github.com/seresistvanandras/EthBench/blob/master/Benchmark/Simple/mishandled.sol 
+ * @author: -
+ * @vulnerable_at_lines: 14
+ */
+
+pragma solidity ^0.4.0;
+contract SendBack {
+    mapping (address => uint) userBalances;
+    function withdrawBalance() {  
+		uint amountToWithdraw = userBalances[msg.sender];
+		userBalances[msg.sender] = 0;
+        // <yes> <report> UNCHECKED_LL_CALLS
+		msg.sender.send(amountToWithdraw);
+	}
+}