added examples

contracts/examples/SampleTokenTimelock.sol

@@ -0,0 +1,32 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC20/ERC20Mintable.sol";
+import "../token/ERC20/ERC20Detailed.sol";
+import "../token/ERC20/TokenTimelock.sol";
+
+/**
+ * @title SampleTimelockToken
+ * @dev Very simple ERC20 Token that can be minted.
+ * It is meant to be used in a tokentimelock contract.
+ */
+contract SampleTimelockToken is ERC20Mintable, ERC20Detailed {
+    constructor() public ERC20Detailed("Sample Timelock Token", "STT", 18) {}
+}
+
+
+/**
+ * @title SampleTokenTimelock
+ * @dev This is an example of a token lock for certain time.
+ */
+
+contract SampleTokenTimelock is TokenTimelock{
+
+    constructor(
+        ERC20Mintable token,
+        address beneficiary,
+        uint256 releaseTime
+    ) 
+    public
+    TokenTimelock(token, beneficiary, releaseTime){}
+
+}