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

Barotrauma/BarotraumaShared/Source/Networking/NetBufferExtensions.cs

@@ -0,0 +1,15 @@
+namespace Barotrauma.Networking
+{
+    static class NetBufferExtensions
+    {
+        //public static void WriteEnum(this NetBuffer buffer, Enum value)
+        //{
+        //    buffer.WriteRangedInteger(0, Enum.GetValues(value.GetType()).Length - 1, Convert.ToInt32(value));
+        //}
+
+        //public static TEnum ReadEnum<TEnum>(this NetBuffer buffer)
+        //{
+        //    return (TEnum)(object)buffer.ReadRangedInteger(0, Enum.GetValues(typeof(TEnum)).Length - 1);
+        //}
+    }
+}