Adds playable instruments, IDropped, IHandSelected and IHandDese… (#368)

* Instrument test.

* Midi stuff

* Some more work

* This actually works now!

* update

* Midi Audio works!

* Lots of stuff, and cool interfaces for items

* Update

* Fix a few things

* It just works

* Move textures to another folder, remove placeholder description from instruments

* Fix warning

* Use renderer enum

* Instruments now use DisposeRenderer method, and send MidiEvents as they receive them. Deletes InstrumentSystem whoo.

* Fix incorrect sprite paths

* Instruments take midi file size check into account when enabling/disabling midi playback buttons

* Fix crash when pressing drop on empty hand.

* Use new renderer return values for midi/input

* Xylophones are no longer handheld instruments, fix their sprites.

* Use new API

* Remove nfluidsynth from solution

* Timing information

* Use IGameTiming.CurTime for timestamps instead

Content.Client/GameObjects/Components/Instruments/InstrumentBoundUserInterface.cs

@@ -0,0 +1,36 @@
+using Content.Client.Instruments;
+using Robust.Client.GameObjects.Components.UserInterface;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Client.GameObjects.Components.Instruments
+{
+    public class InstrumentBoundUserInterface : BoundUserInterface
+    {
+        [ViewVariables]
+        private InstrumentMenu _instrumentMenu;
+
+        public InstrumentComponent Instrument { get; set; }
+
+        public InstrumentBoundUserInterface(ClientUserInterfaceComponent owner, object uiKey) : base(owner, uiKey)
+        {
+        }
+
+        protected override void Open()
+        {
+            if (!Owner.Owner.TryGetComponent<InstrumentComponent>(out var instrument)) return;
+
+            Instrument = instrument;
+            _instrumentMenu = new InstrumentMenu(this);
+            _instrumentMenu.OnClose += Close;
+
+            _instrumentMenu.OpenCentered();
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+            if (!disposing) return;
+            _instrumentMenu?.Dispose();
+        }
+    }
+}