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/SharedApcComponent.cs

@@ -0,0 +1,30 @@
+using System;
+using SS14.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Power
+{
+    [Serializable, NetSerializable]
+    public enum ApcVisuals
+    {
+        ChargeState
+    }
+
+    [Serializable, NetSerializable]
+    public enum ApcChargeState
+    {
+        /// <summary>
+        ///     APC does not have enough power to charge cell (if necessary) and keep powering the area.
+        /// </summary>
+        Lack,
+
+        /// <summary>
+        ///     APC is not full but has enough power.
+        /// </summary>
+        Charging,
+
+        /// <summary>
+        ///     APC battery is full and has enough power.
+        /// </summary>
+        Full,
+    }
+}