Implement order book checksum in kraken

[tingiorni]

I have implemented calculateOrderBookChecksum for kraken using the following

diff --git a/example/src/market_data_simple_subscription/CMakeLists.txt b/example/src/market_data_simple_subscription/CMakeLists.txt
index c72cc750..69a58c0f 100644
--- a/example/src/market_data_simple_subscription/CMakeLists.txt
+++ b/example/src/market_data_simple_subscription/CMakeLists.txt
@@ -2,5 +2,6 @@ set(NAME market_data_simple_subscription)
 project(${NAME})
 add_compile_definitions(CCAPI_ENABLE_SERVICE_MARKET_DATA)
 add_compile_definitions(CCAPI_ENABLE_EXCHANGE_OKX)
+add_compile_definitions(CCAPI_ENABLE_EXCHANGE_KRAKEN)
 add_executable(${NAME} main.cpp)
 add_dependencies(${NAME} boost rapidjson)
diff --git a/example/src/market_data_simple_subscription/main.cpp b/example/src/market_data_simple_subscription/main.cpp
index ca9eff16..018fff20 100644
--- a/example/src/market_data_simple_subscription/main.cpp
+++ b/example/src/market_data_simple_subscription/main.cpp
@@ -36,10 +36,11 @@ int main(int argc, char** argv) {
   SessionOptions sessionOptions;
   SessionConfigs sessionConfigs;
   MyEventHandler eventHandler;
+  sessionOptions.enableCheckOrderBookChecksum = true;
   Session session(sessionOptions, sessionConfigs, &eventHandler);
-  Subscription subscription("okx", "BTC-USDT", "MARKET_DEPTH");
+  Subscription subscription("kraken", "ETH/USDT", "MARKET_DEPTH", "MARKET_DEPTH_MAX=20", "any");
   session.subscribe(subscription);
-  std::this_thread::sleep_for(std::chrono::seconds(10));
+  std::this_thread::sleep_for(std::chrono::seconds(2));
   session.stop();
   std::cout << "Bye" << std::endl;
   return EXIT_SUCCESS;

as example. The output log.txt