Implemented new Anvil saving format, fixed old chunk saving format.

- Added 'Chunk' Interface.
 - Moved old 'Chunk' to 'OldChunk' and replaced dynamic world height reference with '128.
 - Added 'AnvilChunk' implementing the new anvil chunk format.
 - Added temp fixes to FileMcRegionChunkStore.java, TrueZipMcRegionChunkStore.java and ZippedMcRegionChunkStore.java too allow them to read .mca files.
 - Added the new 'IntArrayTag' since the new heightmap tag wasn't recognized.
 - Moved 'getChildTag' to 'NBTUtils'.

src/main/java/com/sk89q/jnbt/NBTOutputStream.java

@@ -157,6 +157,8 @@ public final class NBTOutputStream implements Closeable {
         case NBTConstants.TYPE_COMPOUND:
             writeCompoundTagPayload((CompoundTag) tag);
             break;
+        case NBTConstants.TYPE_INT_ARRAY:
+            writeIntArrayTagPayload((IntArrayTag) tag);
         default:
             throw new IOException("Invalid tag type: " + type + ".");
         }
@@ -308,6 +310,14 @@ public final class NBTOutputStream implements Closeable {
     private void writeEndTagPayload(EndTag tag) {
         /* empty */
     }
+    
+    private void writeIntArrayTagPayload(IntArrayTag tag) throws IOException {
+        int[] data = tag.getValue();
+        os.writeInt(data.length);
+        for (int i = 0; i < data.length; i++) {
+            os.writeInt(data[i]);
+        } 
+    }
 
     public void close() throws IOException {
         os.close();