Allow removing hulls and resend their chunks

HullHider#removeHull stops hiding a hull: it shows the entities and REntities
the hull hid and resends its chunks to everybody who could not view it. A hull
is enabled again by adding and initialising it.

Hull#resendChunks only resends chunks the player has loaded. HullHider now
resends the chunks to non-viewers after initialising a hull itself, so
FightHullHider no longer does it.

HiderCore/src/de/steamwar/hullhider/HullRegion.java

@@ -90,10 +90,22 @@ public final class HullRegion {
         }
     }
 
+    public void forEachChunk(ChunkConsumer executor) {
+        for (int chunkX = minX >> 4; chunkX <= (maxX - 1) >> 4; chunkX++) {
+            for (int chunkZ = minZ >> 4; chunkZ <= (maxZ - 1) >> 4; chunkZ++) {
+                executor.accept(chunkX, chunkZ);
+            }
+        }
+    }
+
     public interface BlockConsumer {
         void accept(int x, int y, int z);
     }
 
+    public interface ChunkConsumer {
+        void accept(int chunkX, int chunkZ);
+    }
+
     @Override
     public String toString() {
         return minX + "," + minY + "," + minZ + "->" + maxX + "," + maxY + "," + maxZ;