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/Farseer Physics Engine 3.5/Common/Decomposition/Seidel/Sink.cs

@@ -0,0 +1,27 @@
+namespace FarseerPhysics.Common.Decomposition.Seidel
+{
+    internal class Sink : Node
+    {
+        public Trapezoid Trapezoid;
+
+        private Sink(Trapezoid trapezoid)
+            : base(null, null)
+        {
+            Trapezoid = trapezoid;
+            trapezoid.Sink = this;
+        }
+
+        public static Sink Isink(Trapezoid trapezoid)
+        {
+            if (trapezoid.Sink == null)
+                return new Sink(trapezoid);
+
+            return trapezoid.Sink;
+        }
+
+        public override Sink Locate(Edge edge)
+        {
+            return this;
+        }
+    }
+}