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/NetSenderChannelBase.cs

@@ -0,0 +1,28 @@
+using System;
+
+namespace Lidgren.Network
+{
+	internal abstract class NetSenderChannelBase
+	{
+		// access this directly to queue things in this channel
+		protected NetQueue<NetOutgoingMessage> m_queuedSends;
+
+		internal abstract int WindowSize { get; }
+
+		internal abstract int GetAllowedSends();
+
+		internal int QueuedSendsCount { get { return m_queuedSends.Count; } }
+
+		internal virtual bool NeedToSendMessages() { return m_queuedSends.Count > 0; }
+
+		public int GetFreeWindowSlots()
+		{
+			return GetAllowedSends() - m_queuedSends.Count;
+		}
+
+		internal abstract NetSendResult Enqueue(NetOutgoingMessage message);
+		internal abstract void SendQueuedMessages(double now);
+		internal abstract void Reset();
+		internal abstract void ReceiveAcknowledge(double now, int sequenceNumber);
+	}
+}