Airlocks rewritten to use appearances, use less ugly sprite from Eris.

Content.Shared/Content.Shared.csproj

@@ -64,6 +64,7 @@
   <ItemGroup>
     <Compile Include="EntryPoint.cs" />
     <Compile Include="GameObjects\Components\Damage\DamageableComponent.cs" />
+    <Compile Include="GameObjects\Components\Doors\SharedDoorComponent.cs" />
     <Compile Include="GameObjects\Components\Inventory\EquipmentSlotDefinitions.cs" />
     <Compile Include="GameObjects\Components\Inventory\InventoryTemplates.cs" />
     <Compile Include="GameObjects\Components\Inventory\SharedInventoryComponent.cs" />

Content.Shared/GameObjects/Components/Doors/SharedDoorComponent.cs

@@ -0,0 +1,22 @@
+using System;
+using SS14.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Doors
+{
+    [NetSerializable]
+    [Serializable]
+    public enum DoorVisuals
+    {
+        VisualState,
+    }
+
+    [NetSerializable]
+    [Serializable]
+    public enum DoorVisualState
+    {
+        Closed,
+        Opening,
+        Open,
+        Closing,
+    }
+}