Added protection against console error spam if island size is zero.

If the protection range is 0 then the caluclations to teleport players
back into the border will result in infinite values and other
strangeness so this prevents that. This is an edge case and only really
happens when the island size has been set wrongly.

src/main/java/world/bentobox/border/listeners/PlayerListener.java

@@ -22,6 +22,7 @@
 import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.event.player.PlayerTeleportEvent.TeleportCause;
 import org.bukkit.event.vehicle.VehicleMoveEvent;
+import org.bukkit.util.NumberConversions;
 import org.bukkit.util.RayTraceResult;
 import org.bukkit.util.Vector;
 
@@ -151,10 +152,15 @@ public void onPlayerLeaveIsland(PlayerMoveEvent e) {
         addon.getIslands().getIslandAt(p.getLocation()).ifPresent(i -> {
             Vector unitVector = i.getProtectionCenter().toVector().subtract(p.getLocation().toVector()).normalize()
                     .multiply(new Vector(1,0,1));
+            if (unitVector.lengthSquared() <= 0D) {
+                // Direction is zero, so nothing to do; cannot move.
+                return;
+            }
             RayTraceResult r = i.getProtectionBoundingBox().rayTrace(p.getLocation().toVector(), unitVector, i.getRange());
-            if (r != null) {
+            if (r != null && checkFinite(r.getHitPosition())) {
                 inTeleport.add(p.getUniqueId());
                 Location targetPos = r.getHitPosition().toLocation(p.getWorld(), p.getLocation().getYaw(), p.getLocation().getPitch());
+
                 if (!e.getPlayer().isFlying() && addon.getSettings().isReturnTeleportBlock()
                         && !addon.getIslands().isSafeLocation(targetPos)) {
                     switch (targetPos.getWorld().getEnvironment()) {
@@ -174,6 +180,11 @@ public void onPlayerLeaveIsland(PlayerMoveEvent e) {
         });
     }
 
+    public boolean checkFinite(Vector toCheck) {
+        return NumberConversions.isFinite(toCheck.getX()) && NumberConversions.isFinite(toCheck.getY())
+                && NumberConversions.isFinite(toCheck.getZ());
+    }
+
     /**
      * Check if the player is outside the island protection zone that they are supposed to be in.
      * @param player - player moving