Full rework of pre-game interface and networking

New features for players:
* Loading for multiplayer. Any save could be used for multiplayer.
* Restart for multiplayer. All clients will restart together.
* Loading from single save.
* Hotseat mixed with network game. Multiple players per client.
* Now connection to server could be cancelled.
* Return to menu on disconnections instead of crashes.
* Restoring of last selected map, save or campaign on next run.

TLDR on important changes in engine code:
* UI: work with server separated from UI
* UI: all explitic blitting replaced with IntObject's
* UI: all new code use smart pointers instead of DISPOSE
* Gameplay always start through lobby controlled by server.
* Threads receiving netpacks now shared for lobby and gameplay.
* Campaigns: heroes for crossover now serialized as JsonNode.

server/NetPacksLobbyServer.cpp

@@ -0,0 +1,250 @@
+/*
+ * NetPacksLobbyServer.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 "CVCMIServer.h"
+#include "CGameHandler.h"
+
+#include "../lib/NetPacksLobby.h"
+#include "../lib/serializer/Connection.h"
+#include "../lib/StartInfo.h"
+
+// Campaigns
+#include "../lib/mapping/CCampaignHandler.h"
+#include "../lib/mapping/CMapService.h"
+#include "../lib/mapping/CMapInfo.h"
+
+bool CLobbyPackToServer::checkClientPermissions(CVCMIServer * srv) const
+{
+	return srv->isClientHost(c->connectionID);
+}
+
+void CLobbyPackToServer::applyOnServerAfterAnnounce(CVCMIServer * srv)
+{
+	// Propogate options after every CLobbyPackToServer
+	srv->updateAndPropagateLobbyState();
+}
+
+bool LobbyClientConnected::checkClientPermissions(CVCMIServer * srv) const
+{
+	return true;
+}
+
+bool LobbyClientConnected::applyOnServer(CVCMIServer * srv)
+{
+	srv->clientConnected(c, names, uuid, mode);
+	// Server need to pass some data to newly connected client
+	clientId = c->connectionID;
+	mode = srv->si->mode;
+	hostClientId = srv->hostClientId;
+	return true;
+}
+
+void LobbyClientConnected::applyOnServerAfterAnnounce(CVCMIServer * srv)
+{
+	// FIXME: we need to avoid senting something to client that not yet get answer for LobbyClientConnected
+	// Until UUID set we only pass LobbyClientConnected to this client
+	c->uuid = uuid;
+	srv->updateAndPropagateLobbyState();
+}
+
+bool LobbyClientDisconnected::checkClientPermissions(CVCMIServer * srv) const
+{
+	if(clientId != c->connectionID)
+		return false;
+
+	if(shutdownServer)
+	{
+		if(!srv->cmdLineOptions.count("run-by-client"))
+			return false;
+
+		if(c->uuid != srv->cmdLineOptions["uuid"].as<std::string>())
+			return false;
+	}
+
+	return true;
+}
+
+bool LobbyClientDisconnected::applyOnServer(CVCMIServer * srv)
+{
+	srv->clientDisconnected(c);
+	return true;
+}
+
+void LobbyClientDisconnected::applyOnServerAfterAnnounce(CVCMIServer * srv)
+{
+	if(c->isOpen())
+	{
+		boost::unique_lock<boost::mutex> lock(*c->mutexWrite);
+		c->close();
+		c->connected = false;
+	}
+
+	if(shutdownServer)
+	{
+		logNetwork->info("Client requested shutdown, server will close itself...");
+		srv->state = EServerState::SHUTDOWN;
+		return;
+	}
+	else if(srv->connections.empty())
+	{
+		logNetwork->error("Last connection lost, server will close itself...");
+		srv->state = EServerState::SHUTDOWN;
+	}
+	else if(c == srv->hostClient)
+	{
+		auto ph = new LobbyChangeHost();
+		auto newHost = *RandomGeneratorUtil::nextItem(srv->connections, CRandomGenerator::getDefault());
+		ph->newHostConnectionId = newHost->connectionID;
+		srv->addToAnnounceQueue(ph);
+	}
+	srv->updateAndPropagateLobbyState();
+}
+
+bool LobbyChatMessage::checkClientPermissions(CVCMIServer * srv) const
+{
+	return true;
+}
+
+bool LobbySetMap::applyOnServer(CVCMIServer * srv)
+{
+	srv->updateStartInfoOnMapChange(mapInfo, mapGenOpts);
+	return true;
+}
+
+bool LobbySetCampaign::applyOnServer(CVCMIServer * srv)
+{
+	srv->si->mapname = ourCampaign->camp->header.filename;
+	srv->si->mode = StartInfo::CAMPAIGN;
+	srv->si->campState = ourCampaign;
+	srv->si->turnTime = 0;
+	bool isCurrentMapConquerable = ourCampaign->currentMap && ourCampaign->camp->conquerable(*ourCampaign->currentMap);
+	for(int i = 0; i < ourCampaign->camp->scenarios.size(); i++)
+	{
+		if(ourCampaign->camp->conquerable(i))
+		{
+			if(!isCurrentMapConquerable || (isCurrentMapConquerable && i == *ourCampaign->currentMap))
+			{
+				srv->setCampaignMap(i);
+			}
+		}
+	}
+	return true;
+}
+
+bool LobbySetCampaignMap::applyOnServer(CVCMIServer * srv)
+{
+	srv->setCampaignMap(mapId);
+	return true;
+}
+
+bool LobbySetCampaignBonus::applyOnServer(CVCMIServer * srv)
+{
+	srv->setCampaignBonus(bonusId);
+	return true;
+}
+
+bool LobbyGuiAction::checkClientPermissions(CVCMIServer * srv) const
+{
+	return srv->isClientHost(c->connectionID);
+}
+
+bool LobbyStartGame::checkClientPermissions(CVCMIServer * srv) const
+{
+	return srv->isClientHost(c->connectionID);
+}
+
+bool LobbyStartGame::applyOnServer(CVCMIServer * srv)
+{
+	try
+	{
+		srv->verifyStateBeforeStart(true);
+	}
+	catch(...)
+	{
+		return false;
+	}
+	// Server will prepare gamestate and we announce StartInfo to clients
+	srv->prepareToStartGame();
+	initializedStartInfo = std::make_shared<StartInfo>(*srv->gh->getStartInfo(true));
+	return true;
+}
+
+void LobbyStartGame::applyOnServerAfterAnnounce(CVCMIServer * srv)
+{
+	srv->startGameImmidiately();
+}
+
+bool LobbyChangeHost::checkClientPermissions(CVCMIServer * srv) const
+{
+	return srv->isClientHost(c->connectionID);
+}
+
+bool LobbyChangeHost::applyOnServer(CVCMIServer * srv)
+{
+	return true;
+}
+
+bool LobbyChangeHost::applyOnServerAfterAnnounce(CVCMIServer * srv)
+{
+	return srv->passHost(newHostConnectionId);
+}
+
+bool LobbyChangePlayerOption::checkClientPermissions(CVCMIServer * srv) const
+{
+	if(srv->isClientHost(c->connectionID))
+		return true;
+
+	if(vstd::contains(srv->getAllClientPlayers(c->connectionID), color))
+		return true;
+
+	return false;
+}
+
+bool LobbyChangePlayerOption::applyOnServer(CVCMIServer * srv)
+{
+	switch(what)
+	{
+	case TOWN:
+		srv->optionNextCastle(color, direction);
+		break;
+	case HERO:
+		srv->optionNextHero(color, direction);
+		break;
+	case BONUS:
+		srv->optionNextBonus(color, direction);
+		break;
+	}
+	return true;
+}
+
+bool LobbySetPlayer::applyOnServer(CVCMIServer * srv)
+{
+	srv->setPlayer(clickedColor);
+	return true;
+}
+
+bool LobbySetTurnTime::applyOnServer(CVCMIServer * srv)
+{
+	srv->si->turnTime = turnTime;
+	return true;
+}
+
+bool LobbySetDifficulty::applyOnServer(CVCMIServer * srv)
+{
+	srv->si->difficulty = vstd::abetween(difficulty, 0, 4);
+	return true;
+}
+
+bool LobbyForceSetPlayer::applyOnServer(CVCMIServer * srv)
+{
+	srv->si->playerInfos[targetPlayerColor].connectedPlayerIDs.insert(targetConnectedPlayer);
+	return true;
+}