Added GameInstance class

- available as global GAME
- integrates LOCPLINT (CPlayerInterface)
- integrates CGI->mh (CMapHandler)
- integrates CSH (CServerHandler)

client/GameInstance.cpp

@@ -0,0 +1,60 @@
+/*
+ * GameInstance.cpp, part of VCMI engine
+ *
+ * Authors: listed in file AUTHORS in main folder
+ *
+ * License: GNU General Public License v2.0 or later
+ * Full text of license available in license.txt file, in main folder
+ *
+ */
+#include "StdInc.h"
+#include "GameInstance.h"
+
+#include "CServerHandler.h"
+#include "mapView/mapHandler.h"
+
+std::unique_ptr<GameInstance> GAME = nullptr;
+
+GameInstance::GameInstance()
+	: serverInstance(std::make_unique<CServerHandler>())
+	, interfaceInstance(nullptr)
+{
+}
+
+GameInstance::~GameInstance() = default;
+
+CServerHandler & GameInstance::server()
+{
+	if (!serverInstance)
+		throw std::runtime_error("Invalid access to GameInstance::server");
+
+	return *serverInstance;
+}
+
+CMapHandler & GameInstance::map()
+{
+	if (!mapInstance)
+		throw std::runtime_error("Invalid access to GameInstance::map");
+
+	return *mapInstance;
+}
+
+CPlayerInterface * GameInstance::interface()
+{
+	return interfaceInstance;
+}
+
+void GameInstance::setServerInstance(std::unique_ptr<CServerHandler> ptr)
+{
+	serverInstance = std::move(ptr);
+}
+
+void GameInstance::setMapInstance(std::unique_ptr<CMapHandler> ptr)
+{
+	mapInstance = std::move(ptr);
+}
+
+void GameInstance::setInterfaceInstance(CPlayerInterface * ptr)
+{
+	interfaceInstance = std::move(ptr);
+}