fix typo in documentation
Extract JobQueue interface and change the former JobQueue to AsyncJobQueue.
Make JobHandle a nested class of Job.
Move some code around to reflect previous changes.
Synchronous job queue (jobs executed from main loop).
Add comparison functors for SystemPath to compare by sector only and by system only.
Extract templated base class from SectorCache.
Rename SectorCache.* to GalaxyCache.*
Don't assume that the master cache is the global cache.
Rename Sector::GetSystemPath to Sector::GetPath.
Derive StarSystemCache from GalaxyObjectCache template.
Add a finish callback for cache filling.
Update StarSystem cache when switching spaces.
Galaxy cache usage statistics.