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/Documentation/PacketLayout.txt

@@ -0,0 +1,17 @@
+
+PER MESSAGE:
+7 bits - NetMessageType
+1 bit - Is a message fragment?
+
+[8 bits NetMessageLibraryType, if NetMessageType == Library]
+
+[16 bits sequence number, if NetMessageType >= UserSequenced]
+
+8/16 bits - Payload length in bits (variable size ushort)
+
+[16 bits fragments group id, if fragmented]
+[16 bits fragments total count, if fragmented]
+[16 bits fragment number, if fragmented]
+
+[x - Payload] if length > 0
+