try to clean up a bit better

src/stratagus/script_player.cpp

@@ -94,8 +94,8 @@ void CPlayer::Load(lua_State *l)
 {
 	const int args = lua_gettop(l);
 
-	this->Units.resize(0);
-	this->FreeWorkers.resize(0);
+	this->Units.clear();
+	this->FreeWorkers.clear();
 
 	// j = 0 represent player Index.
 	for (int j = 1; j < args; ++j) {

src/unit/unit.cpp

@@ -491,6 +491,9 @@ void CUnit::Release(bool final)
 		DebugPrint("unit already free\n");
 		return;
 	}
+	if (PlayerSlot != static_cast<size_t>(-1)) {
+		Player->RemoveUnit(*this);
+	}
 	Assert(Orders.size() == 1);
 	// Must be removed before here
 	Assert(Removed);

src/unit/unit_manager.cpp

@@ -120,6 +120,7 @@ void CUnitManager::ReleaseUnit(CUnit *unit)
 		unit->UnitManagerData.unitSlot = -1;
 		units.pop_back();
 	}
+	Assert(unit->PlayerSlot == -1);
 	releasedUnits.push_back(unit);
 	unit->ReleaseCycle = GameCycle + 500; // can be reused after this time
 	//Refs = GameCycle + (NetworkMaxLag << 1); // could be reuse after this time