Add SteamController implementation

This adds a Steam Shortcuts, Desktop Mode, and X360 Emulation
- Supports all Steam Shortcuts (including on-screen keyboard, and brightness)
- Supports Desktop mode (with a scroll on left pad and left stick), and trackpoint (on right stick)
- Supports X360 mode: hold Options for 1s to switch between Desktop and X360
- Holding Steam button enables Desktop like controls and stops passing all inputs to X360

SteamController/Devices/SteamController.cs

@@ -0,0 +1,65 @@
+using hidapi;
+using PowerControl.External;
+using static CommonHelpers.Log;
+
+namespace SteamController.Devices
+{
+    public partial class SteamController : IDisposable
+    {
+        public const ushort SteamVendorID = 0x28DE;
+        public const ushort SteamProductID = 0x1205;
+        public const int ReadTimeout = 50;
+
+        private hidapi.HidDevice neptuneDevice;
+
+        public SteamController()
+        {
+            InitializeButtons();
+            InitializeActions();
+
+            neptuneDevice = new hidapi.HidDevice(SteamVendorID, SteamProductID, 64);
+            neptuneDevice.OpenDevice();
+        }
+
+        public void Dispose()
+        {
+        }
+
+        public bool Updated { get; private set; }
+
+        internal void Reset()
+        {
+            foreach (var action in AllActions)
+                action.Reset();
+        }
+
+        private void BeforeUpdate(byte[] buffer)
+        {
+            foreach (var action in AllActions)
+                action.BeforeUpdate(buffer, this);
+        }
+
+        internal void BeforeUpdate()
+        {
+            byte[] data = neptuneDevice.Read(ReadTimeout);
+            if (data == null)
+            {
+                Reset();
+                Updated = false;
+                return;
+            }
+
+            BeforeUpdate(data);
+            Updated = true;
+        }
+
+        internal void Update()
+        {
+            foreach (var action in AllActions)
+                action.Update();
+
+            UpdateLizardButtons();
+            UpdateLizardMouse();
+        }
+    }
+}