- fixed #1643 -> hero placeholder handling

- fixed bug when loading victory/loss conditions of the 3rd scenario in the first ROE campaign
- fixed bug when loading artifacts to hero of the 3rd scenario in the first ROE campaign (due to corrupt H3M map)
- implemented function object to quickly find a object by it's sub ID in a list
- added netbackbase.h to header list in CMake
- removed false message which said that the server loaded the map successfully

lib/mapping/CCampaignHandler.cpp

@@ -337,6 +337,23 @@ const CGHeroInstance * CCampaignScenario::strongestHero( PlayerColor owner ) con
 	return i == ownedHeroes.end() ? nullptr : *i;
 }
 
+std::vector<CGHeroInstance *> CCampaignScenario::getLostCrossoverHeroes() const
+{
+	std::vector<CGHeroInstance *> lostCrossoverHeroes;
+	if(conquered)
+	{
+		for(auto hero : placedCrossoverHeroes)
+		{
+			auto it = range::find_if(crossoverHeroes, CGObjectInstanceBySubIdFinder(hero));
+			if(it == crossoverHeroes.end())
+			{
+				lostCrossoverHeroes.push_back(hero);
+			}
+		}
+	}
+	return std::move(lostCrossoverHeroes);
+}
+
 bool CScenarioTravel::STravelBonus::isBonusForHero() const
 {
 	return type == SPELL || type == MONSTER || type == ARTIFACT || type == SPELL_SCROLL || type == PRIMARY_SKILL
@@ -376,6 +393,11 @@ const CCampaignScenario & CCampaignState::getCurrentScenario() const
 	return camp->scenarios[*currentMap];
 }
 
+CCampaignScenario & CCampaignState::getCurrentScenario()
+{
+	return camp->scenarios[*currentMap];
+}
+
 ui8 CCampaignState::currentBonusID() const
 {
 	return chosenCampaignBonuses.at(*currentMap);