removed compiler warning in level_manager.cpp

src/gameplay/level_manager.cpp

@@ -168,7 +168,7 @@ namespace gdw {
 		}
 
 		std::vector<unsigned long long> del_queue;
-		for (int i = 0; i < victims_.size(); i++) {
+		for (auto i = 0u; i < victims_.size(); i++) {
 			auto victim = engine_.entity_manager().resolve(victims_[i]);
 			if (!victim) continue;
 
@@ -209,7 +209,7 @@ namespace gdw {
 		unsigned int item_drop_chance = 100; // percent
 		for (auto &item : items_to_create) {
 			srand(time(0) * time(0));
-			if (rand() % 100 <= item_drop_chance) {
+			if (rand() % 100u <= item_drop_chance) {
 				srand(time(0) * time(0));
 				constexpr int max = item_type::type_count;
 				constexpr int min = 0;