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/YNode.cs

@@ -0,0 +1,29 @@
+namespace FarseerPhysics.Common.Decomposition.Seidel
+{
+    internal class YNode : Node
+    {
+        private Edge _edge;
+
+        public YNode(Edge edge, Node lChild, Node rChild)
+            : base(lChild, rChild)
+        {
+            _edge = edge;
+        }
+
+        public override Sink Locate(Edge edge)
+        {
+            if (_edge.IsAbove(edge.P))
+                return RightChild.Locate(edge); // Move down the graph
+
+            if (_edge.IsBelow(edge.P))
+                return LeftChild.Locate(edge); // Move up the graph
+
+            // s and segment share the same endpoint, p
+            if (edge.Slope < _edge.Slope)
+                return RightChild.Locate(edge); // Move down the graph
+
+            // Move up the graph
+            return LeftChild.Locate(edge);
+        }
+    }
+}