Updated to MonoGame 3.6 + Directory refactor

- Barotrauma's projects are in the Barotrauma directory
- All libraries are in the Libraries directory
- MonoGame is now managed by NuGet, rather than referenced from the installed files (TODO: consider using PCL for easier cross-platform development?)
- NuGet libraries are not included in the repo, as getting the latest versions automatically should be preferred
- Removed Content/effects.mgfx as it didn't seem to be used anywhere
- Removed some references to Subsurface directory
- Renamed Launcher2 to Launcher

Libraries/Lidgren.Network/NetTuple.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Lidgren.Network
+{
+	// replace with BCL 4.0 Tuple<> when appropriate
+	internal struct NetTuple<A, B>
+	{
+		public A Item1;
+		public B Item2;
+
+		public NetTuple(A item1, B item2)
+		{
+			Item1 = item1;
+			Item2 = item2;
+		}
+	}
+}