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/BarotraumaClient/Source/Sprite/SpriteSheet.cs

@@ -0,0 +1,24 @@
+using Microsoft.Xna.Framework;
+using System;
+using System.Xml.Linq;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace Barotrauma
+{
+    partial class SpriteSheet : Sprite
+    {
+        public override void Draw(SpriteBatch spriteBatch, Vector2 pos, Color color, Vector2 origin, float rotate, Vector2 scale, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = default(float?))
+        {
+            if (texture == null) return;
+
+            spriteBatch.Draw(texture, pos + offset, sourceRects[0], color, rotation + rotate, origin, scale, spriteEffect, depth == null ? this.depth : (float)depth);
+        }
+
+        public void Draw(SpriteBatch spriteBatch, int spriteIndex, Vector2 pos, Color color, Vector2 origin, float rotate, Vector2 scale, SpriteEffects spriteEffect = SpriteEffects.None, float? depth = default(float?))
+        {
+            if (texture == null) return;
+
+            spriteBatch.Draw(texture, pos + offset, sourceRects[spriteIndex], color, rotation + rotate, origin, scale, spriteEffect, depth == null ? this.depth : (float)depth);
+        }
+    }
+}