LitJson.JsonException: Can't assign value '2347089724' (type System.UInt32) to type System.Int64

告诉LitJson一种转换方式：

private static void RegisterBaseImporters ()
{
    //...

    // 拓展;
    RegisterImporter(base_importers_table, typeof(uint), typeof(long), (object value) => { return Convert.ToInt64(value); });
    RegisterImporter(base_importers_table, typeof(long), typeof(double), (object value) => { return Convert.ToDouble(value); });
}