void Redo()
{
InkPlayerHistoryItem item = storyStateHistory.Redo();
story.state.LoadJson(item.inkStateJSON);
storyHistory = new List <InkPlayerHistoryContentItem>(item.storyHistory);
ScrollToBottom();
}
void AddToHistory()
{
InkPlayerHistoryItem historyItem = new InkPlayerHistoryItem(story.state.ToJson(), new List <InkPlayerHistoryContentItem>(storyHistory));
storyStateHistory.AddToUndoHistory(historyItem);
}