Include OpenGL version string in sysinfo.

OpenRA.Game/Graphics/IGraphicsDevice.cs

@@ -78,6 +78,8 @@ namespace OpenRA
 
 		IHardwareCursor CreateHardwareCursor(string name, Size size, byte[] data, int2 hotspot);
 		void SetHardwareCursor(IHardwareCursor cursor);
+
+		string GLVersion { get; }
 	}
 
 	public interface IVertexBuffer<T> : IDisposable

OpenRA.Game/Renderer.cs

@@ -273,5 +273,10 @@ namespace OpenRA
 		{
 			return Device.SetClipboardText(text);
 		}
+
+		public string GLVersion
+		{
+			get { return Device.GLVersion; }
+		}
 	}
 }