// loads the sandard game data
private void LoadContentPackData(string contentPackName)
{
// load standard data packs
Empire.AddDataPack(Engine.Instance.Content.GetAsset <Stream>($"{contentPackName}:XML/GameData/Empires"));
Building.AddDataPack(Engine.Instance.Content.GetAsset <Stream>($"{contentPackName}:XML/GameData/Buildings"));
Unit.AddDataPack(Engine.Instance.Content.GetAsset <Stream>($"{contentPackName}:XML/GameData/Units"));
Tech.AddDataPack(Engine.Instance.Content.GetAsset <Stream>($"{contentPackName}:XML/GameData/Technologies"));
SocialPolicy.AddDataPack(Engine.Instance.Content.GetAsset <Stream>($"{contentPackName}:XML/GameData/SocialPolicies"));
}