Fix Kush main menu background

It looked ok as long as the window had a 16:9 aspect ratio, however
default window size is 4:3 which squishes the balcony.

Add a horizontal alignment support for background layers, which allows
to fix this issue for any aspect ratio.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

binaries/data/mods/public/gui/pregame/BackgroundHandler.js

@@ -29,6 +29,20 @@ class BackgroundLayer
 				"bottom": backgroundsSize.bottom
 			};
 		}
+		else if (this.layer.halign)
+		{
+			const left = ({
+				"left": 0.0,
+				"center": (backgroundsSize.right - width) / 2,
+				"right": backgroundsSize.right - width,
+			}[this.layer.halign] || 0.0) + offset;
+			this.background.size = {
+				"left": left,
+				"top": backgroundsSize.top,
+				"right": left + width,
+				"bottom": backgroundsSize.bottom
+			};
+		}
 		else
 		{
 			const right = backgroundsSize.right / 2 + offset;

binaries/data/mods/public/gui/pregame/backgrounds/background.js

@@ -59,7 +59,8 @@ export const backgrounds = {
 		{
 			"offset": (time, width) => -0.1,
 			"sprite": "background-kush1-4",
-			"tiling": true
+			"tiling": false,
+			"halign": "right"
 		}
 	],