fixes for running on older versions of .net and windows

[Terricide]

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[gsidsid]

I needed to comment out the following lines in WebRtcSession.cs to get the example working:

Spitfire.OnDataChannelConnecting += Spitfire_OnDataChannelConnecting;
Spitfire.OnDataChannelClosing += Spitfire_OnDataChannelClosing;
Spitfire.OnDataMessage += Spitfire_OnDataMessage;
Spitfire.OnDataBinaryMessage += Spitfire_OnDataBinaryMessage;

Also in Program.cs it may be more informative to change
Console.WriteLine("Meesage from peer:" + ex); to Console.WriteLine("Meesage from peer:" + ex.Data);

But other than that this should really be merged in