Fix for minor bug in border knockback code for worlds that have a single layer bedrock base at Y level 1.

The bug was that locations at Y level 1 were never treated as safe locations for border knockback, even though they can be safe on a world which has only a flat 1-block height layer of bedrock at the bottom. For reference, normal worlds have multiple layers of bedrock at the bottom.

src/main/java/com/wimbli/WorldBorder/BorderData.java

@@ -315,7 +315,7 @@ public class BorderData
 			);
 	}
 
-	private static final int limBot = 1;
+	private static final int limBot = 0;
 
 	// find closest safe Y position from the starting position
 	private double getSafeY(World world, int X, int Y, int Z, boolean flying)