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/TODO.txt

@@ -0,0 +1,17 @@
+
+Completed features:
+* Message coalescing
+* Peer, connection statistics
+* Lag, loss and duplication simulation for testing
+* Connection approval
+* Throttling
+* Clock synchronization to detect jitter per packet (NetTime.RemoteNow)
+* Peer discovery
+* Message fragmentation
+
+Missing features:
+* Receipts 25% done, need design
+* More realistic lag/loss (lumpy)
+* Detect estimated packet loss
+* More advanced ack packet
+