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/NetRandomSeed.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Threading;
+
+namespace Lidgren.Network
+{
+	/// <summary>
+	/// Class for generating random seeds
+	/// </summary>
+	public static class NetRandomSeed
+	{
+		private static int m_seedIncrement = -1640531527;
+
+		/// <summary>
+		/// Generates a 32 bit random seed
+		/// </summary>
+		[CLSCompliant(false)]
+		public static uint GetUInt32()
+		{
+			ulong seed = GetUInt64();
+			uint low = (uint)seed;
+			uint high = (uint)(seed >> 32);
+			return low ^ high;
+		}
+
+		/// <summary>
+		/// Generates a 64 bit random seed
+		/// </summary>
+		[CLSCompliant(false)]
+		public static ulong GetUInt64()
+		{
+			var guidBytes = Guid.NewGuid().ToByteArray();
+			ulong seed =
+				((ulong)guidBytes[0] << (8 * 0)) |
+				((ulong)guidBytes[1] << (8 * 1)) |
+				((ulong)guidBytes[2] << (8 * 2)) |
+				((ulong)guidBytes[3] << (8 * 3)) |
+				((ulong)guidBytes[4] << (8 * 4)) |
+				((ulong)guidBytes[5] << (8 * 5)) |
+				((ulong)guidBytes[6] << (8 * 6)) |
+				((ulong)guidBytes[7] << (8 * 7));
+
+			return seed ^ NetUtility.GetPlatformSeed(m_seedIncrement);
+		}
+	}
+}