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/NetUnreliableSequencedReceiver.cs

@@ -0,0 +1,33 @@
+using System;
+
+namespace Lidgren.Network
+{
+	internal sealed class NetUnreliableSequencedReceiver : NetReceiverChannelBase
+	{
+		private int m_lastReceivedSequenceNumber = -1;
+
+		public NetUnreliableSequencedReceiver(NetConnection connection)
+			: base(connection)
+		{
+		}
+
+		internal override void ReceiveMessage(NetIncomingMessage msg)
+		{
+			int nr = msg.m_sequenceNumber;
+
+			// ack no matter what
+			m_connection.QueueAck(msg.m_receivedMessageType, nr);
+
+			int relate = NetUtility.RelativeSequenceNumber(nr, m_lastReceivedSequenceNumber + 1);
+			if (relate < 0)
+			{
+				m_connection.m_statistics.MessageDropped();
+				m_peer.LogVerbose("Received message #" + nr + " DROPPING DUPLICATE");
+				return; // drop if late
+			}
+
+			m_lastReceivedSequenceNumber = nr;
+			m_peer.ReleaseMessage(msg);
+		}
+	}
+}