Method undo

BambooTracker/command/command_manager.cpp:22–40

}

bool CommandManager::undo()
{
	if (undoStack_.empty()) return true;

	CommandIPtr command = std::move(undoStack_.back());
	if (!command) return false;

	if (command->undo()) {
		// Push and pop history stacks.
		undoStack_.pop_back();
		redoStack_.push_back(std::move(command));
		return true;
	}
	else {
		// Rollback.
		command->redo();
		return false;
	}
}

bool CommandManager::redo()
{