Better inventory window, inventory buttons on game HUD.

Part of #272

Content.Client/GameObjects/Components/HUD/Inventory/InventoryInterfaceController.cs

@@ -0,0 +1,79 @@
+using System;
+using Content.Client.UserInterface;
+using Content.Shared.GameObjects.Components.Inventory;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.CustomControls;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.IoC;
+
+namespace Content.Client.GameObjects
+{
+    public abstract class InventoryInterfaceController : IDisposable
+    {
+        // ReSharper disable once UnassignedGetOnlyAutoProperty
+        [field: Dependency] protected IGameHud GameHud { get; }
+
+        protected InventoryInterfaceController(ClientInventoryComponent owner)
+        {
+            Owner = owner;
+        }
+
+        public virtual void Initialize()
+        {
+
+        }
+
+        public abstract SS14Window Window { get; }
+        protected ClientInventoryComponent Owner { get; }
+
+        public virtual void PlayerAttached()
+        {
+            GameHud.InventoryButtonVisible = true;
+            GameHud.InventoryButtonToggled = b =>
+            {
+                if (b)
+                {
+                    Window.Open();
+                }
+                else
+                {
+                    Window.Close();
+                }
+            };
+        }
+
+        public virtual void PlayerDetached()
+        {
+            GameHud.InventoryButtonVisible = false;
+            Window.Close();
+        }
+
+        public virtual void Dispose()
+        {
+        }
+
+        public virtual void AddToSlot(EquipmentSlotDefines.Slots slot, IEntity entity)
+        {
+        }
+
+        public virtual void RemoveFromSlot(EquipmentSlotDefines.Slots slot)
+        {
+        }
+
+        protected void RemoveFromInventory(BaseButton.ButtonEventArgs args)
+        {
+            args.Button.Pressed = false;
+            var control = (InventoryButton) args.Button.Parent;
+
+            Owner.SendUnequipMessage(control.Slot);
+        }
+
+        protected void AddToInventory(BaseButton.ButtonEventArgs args)
+        {
+            args.Button.Pressed = false;
+            var control = (InventoryButton) args.Button.Parent;
+
+            Owner.SendEquipMessage(control.Slot);
+        }
+    }
+}