When using ChunkWorx to generate multiple chunks, the server would sometimes fail an assert because it would generate a chunk even when it was successfully loaded. This was caused by chunks queued in cWorld's m_SetChunkDataQueue and thus being marked as "InQueue" although they were already loaded.
Solved by adding a new parameter to chunk coord callbacks specifying whether the operation succeeded or failed, and using that instead of the chunk presence flag to decide whether to generate or not.
This should theoretically speed it up, since less data is copied back and forth.
Also implemented a possibly more cache-friendly blocklight starter algorithm (PrepareBlockLight2()), is disabled by default, needs perf testing.
