Creates framing chunks

AnvilWorldProvider.cs

	        int createdChunks = 0;
            Stopwatch sw = new Stopwatch();
            sw.Start();

            foreach (KeyValuePair<ChunkCoordinates, ChunkColumn> valuePair in _chunkCache)
            {
                ChunkCoordinates chunkCoordinates = valuePair.Key;
                ChunkColumn chunkColumn = valuePair.Value;

                if (chunkColumn != null && !chunkColumn.isAllAir)
                {
                    for (int startX = chunkCoordinates.X - 1; startX <= chunkCoordinates.X + 1; startX++)
                    {
                        for (int startZ = chunkCoordinates.Z - 1; startZ <= chunkCoordinates.Z + 1; startZ++)
                        {
                            ChunkCoordinates surroundingChunkCoordinates = new ChunkCoordinates(startX, startZ);

                            if (!surroundingChunkCoordinates.Equals(chunkCoordinates))
                            {
                                ChunkColumn surroundingChunkColumn;

                                _chunkCache.TryGetValue(surroundingChunkCoordinates, out surroundingChunkColumn);

                                if (surroundingChunkColumn == null)
                                {
                                    ChunkColumn airColumn = new ChunkColumn
                                    {
                                        x = startX,
                                        z = startZ,
                                        isAllAir = true
                                    };

                                    airColumn.GetBatch();

                                    _chunkCache[chunkCoordinates] = airColumn;
                                    createdChunks++;
                                }
                            }
                        }
                    }
                }
            }

            sw.Stop();
            Log.Info("Created " + createdChunks + " air chunks in " + sw.ElapsedMilliseconds + "ms");
            return createdChunks;