APC & SMES appearances. (#78)

* CEV-Eris SMES sprite as RSI.

Has been modified so that the light overlay states use alpha blending.

* Add tiny glow to SMES display sprite.

* Appearances work v2

* More WiP

* RoundToLevels works correctly on even level counts now.

* SMES -> Smes because MS guidelines.

* CEV-Eris APC sprite.

* APC visuals.

* Reduce SMES scale again to normal levels.

* Update submodule

Content.Shared/GameObjects/Components/Power/PowerShared.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using SS14.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Power
+{
+    [Serializable, NetSerializable]
+    public enum ChargeState
+    {
+        Still,
+        Charging,
+        Discharging,
+    }
+}