Added new art, also added stairs and walls to building menu

Assets/Scripts/Game/Buildings/BuildingManager.cs

@@ -7,13 +7,13 @@ namespace Fruitomation.Game
     {
         private class BuildingInfo
         {
-            public BuildingInfo(BuildingBase b, RectTransform rt)
+            public BuildingInfo(Building b, RectTransform rt)
             {
                 Building = b;
                 Rect = rt;
             }
 
-            public BuildingBase Building { get; }
+            public Building Building { get; }
             public RectTransform Rect { get; }
         }
 
@@ -26,7 +26,7 @@ namespace Fruitomation.Game
             GameObject go = Instantiate(prefab, transform);
             BuildingInfo info = new
             (
-                go.GetComponent<BuildingBase>(),
+                go.GetComponent<Building>(),
                 go.GetComponent<RectTransform>()
             );