Add SmartToken contract with tests and documentation

add missing public identifier in approveData in SmartToken contract

remove constact from showMessage function in message helper contract

move Message helper contract to mocks folder

move SmartTokenMock contract to mocks folder

contracts/mocks/MessageHelper.sol

@@ -0,0 +1,25 @@
+pragma solidity ^0.4.11;
+
+contract MessageHelper {
+
+  event Show(bytes32 b32, uint256 number, string text);
+
+  function showMessage(
+    bytes32 message, uint256 number, string text
+  ) returns (bool) {
+    Show(message, number, text);
+    return true;
+  }
+
+  function fail() {
+    throw;
+  }
+
+  function call(address to, bytes data) returns (bool) {
+    if (to.call(data))
+      return true;
+    else
+      return false;
+  }
+
+}