Add async session save method, random tweaks

Torch.API/IMultiplayer.cs

@@ -13,8 +13,7 @@ namespace Torch.API
         event Action<IChatItem> MessageReceived;
         Dictionary<ulong, IPlayer> Players { get; }
         List<IChatItem> Chat { get; }
-        void SendMessage(string message);
-        void SendMessage(string message, long playerId, string author = "Server", string font = MyFontEnum.Blue);
+        void SendMessage(string message, string author = "Server", long playerId = 0, string font = MyFontEnum.Blue);
         void KickPlayer(ulong id);
         void BanPlayer(ulong id, bool banned = true);
         IMyPlayer GetPlayerBySteamId(ulong id);

Torch.API/ITorchBase.cs

@@ -27,6 +27,7 @@ namespace Torch.API
     public interface ITorchServer : ITorchBase
     {
         bool IsRunning { get; }
+        string InstancePath { get; }
     }
 
     public interface ITorchClient : ITorchBase