Integrated checkpoints into normal levels.
Various fixes.
ASync.EveryXSeconds
ASync.WithDelay takes Act now.
Better unity editor logging.
Merge commit '6929606b5dc8afa870514ca73430aca6af0ce854' into shield

Conflicts:
	vendor/tlplib/Assets/Vendor/TLPLib/Concurrent/ASync.cs
Use LOG_DEBUG for conditional debug, because DEBUG is used by Unity.