perf(render): "Pillaged improvement" image packed with improvement icons to allow mods to override it

Author: yairm210

android/Images.Icons/ImprovementIcons/Pillaged.png

@@ -767,6 +767,13 @@ OtherIcons/Fire
   orig: 115, 115
   offset: 0, 0
   index: -1
+ImprovementIcons/Pillaged
+  rotate: false
+  xy: 4, 865
+  size: 115, 115
+  orig: 115, 115
+  offset: 0, 0
+  index: -1
 OtherIcons/ForwardArrow
   rotate: false
   xy: 1280, 1100

android/assets/Icons.atlas

@@ -216,7 +216,7 @@ class PortraitImprovement(name: String, size: Float, dim: Boolean = false, isPil
             background.color.a = 0.7f
         }
         if (isPillaged) {
-            val pillagedIcon = ImageGetter.getImage("OtherIcons/Fire")
+            val pillagedIcon = ImageGetter.getImage("ImprovementIcons/Pillaged")
             pillagedIcon.setSize(width/2, height/2)
             pillagedIcon.setPosition(width, 0f, Align.bottomRight)
             addActor(pillagedIcon)
@@ -238,7 +238,8 @@ class PortraitImprovement(name: String, size: Float, dim: Boolean = false, isPil
         return Color.WHITE
     }
 
-    override fun draw(batch: Batch?, parentAlpha: Float) = super.draw(batch, parentAlpha)
+    override fun draw(batch: Batch?, parentAlpha: Float) = 
+        super.draw(batch, parentAlpha)
 }
 
 class PortraitNation(name: String, size: Float) : Portrait(Type.Nation, name, size, size*0.1f) {

core/src/com/unciv/ui/images/Portrait.kt

@@ -38,16 +38,17 @@ If you use external tools and multiple atlases, you will need to maintain this f
 A large number of atlases may be the result of having very large icons.
 We find that 100x100 pixels is good enough for most icons.
 
-#### Circle icons
+#### Rendering performance
 
 To allow for faster rendering for icons, which has a major performance effect, you can copy the ["OtherIcons/circle.png"](https://github.com/yairm210/Unciv/blob/master/android/Images.Icons/OtherIcons/Circle.png) to:
 
-- "ImprovementIcons/Circle.png" for improvements
+- "ImprovementIcons/Circle.png" for improvements - you can also copy "ImprovementIcons/Pillaged.png" for it to be packed with your icons
 - "ResourceIcons/Circle.png" for resources
 - "TechIcons/Circle.png" for technologies
 - "ConstructionIcons/Circle.png" for buildings and units
 - "StatIcons/Circle.png" for stats
 
+You should only do so if the mod icons will be the *majority* of the icons for each category, NOT if you're adding on a few more.
 
 ### Texture packer settings