- improved performance on paper servers by using chunk coordinates instead of chunk instances to check if the chunk was generated
- moved generation stuff to lib/generation
- Added interface GenerationTask
- added method to GenerationManager that creates a task depending on the server type
- added generation task for paper and spigot (to profit from async chunk loading)
- fixed removegentask command
- added autostop of generation task after a certain amout of chunks or at the world border
- added SqlUpdateManager to check if tables need to be created or updated