Eternity Engine Game Configuration: Update skew properties (#931)

Build/Configurations/Includes/Eternity_misc.cfg

@@ -151,21 +151,21 @@ universalfields
 		skew_top_type
 		{
 			type = 16;
-			enum = "skew_type_top_bottom";
+			enum = "skew_type";
 			default = "none";
 		}
 
 		skew_middle_type
 		{
 			type = 16;
-			enum = "skew_type_middle";
+			enum = "skew_type";
 			default = "none";
 		}
 
 		skew_bottom_type
 		{
 			type = 16;
-			enum = "skew_type_top_bottom";
+			enum = "skew_type";
 			default = "none";
 		}
 	}
@@ -696,14 +696,7 @@ enums
 		6 = "Copy texture and type; numeric model";
 	}
 
-	skew_type_top_bottom
-	{
-		none = "None";
-		front = "Skew to front-sector slope";
-		back = "Skew to back-sector slope";
-	}
-
-	skew_type_middle
+	skew_type
 	{
 		none = "None";
 		front_floor = "Skew to front-sector floor slope";