Some of these are copies from the respective origins from mtg,
to make sure we have headers everywhere listing the proper code.
I've relicensed spectator_mode from WT*PL to LGPL-2.1. No other
licenses were changed.
It appears we're fixing light, which then immediately gets
overwritten with broken light from the write_to_map() VM method.
We postpone this 1+ server tick to assure that the write_to_map()
has committed entirely. This may result in more block data being
sent to the client.
