Fix some missing return values

src/gui/game/GameController.cpp

@@ -1401,8 +1401,7 @@ std::string GameController::ElementResolve(int type, int ctype)
 		else if (type >= 0 && type < PT_NUM && gameModel->GetSimulation()->elements)
 			return std::string(gameModel->GetSimulation()->elements[type].Name);
 	}
-	else
-		return "";
+	return "";
 }
 
 bool GameController::IsValidElement(int type)

src/lua/LuaScriptInterface.cpp

@@ -1999,7 +1999,7 @@ int LuaScriptInterface::elements_loadDefault(lua_State * l)
 	luacon_model->BuildMenus();
 	luacon_sim->init_can_move();
 	std::fill(luacon_ren->graphicscache, luacon_ren->graphicscache+PT_NUM, gcache_item());
-
+	return 0;
 }
 
 int LuaScriptInterface::elements_allocate(lua_State * l)
@@ -2296,6 +2296,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		}
 		else
 			return luaL_error(l, "Invalid element property");
+		return 0;
 	}
 	else
 	{

src/lua/TPTScriptInterface.cpp

@@ -190,6 +190,7 @@ AnyType TPTScriptInterface::eval(std::deque<std::string> * words)
 	case TypeString:
 		return StringType(word);
 	}
+	return StringType(word);
 }
 
 std::string TPTScriptInterface::FormatCommand(std::string command)