Singleplayer update

- Fixed bug when multiple messages could share the same sequence number,
discarding all of them except the first
- Implemented generic methods to load a scene
- Fixed the scene loading algorithm to save the new scene/pos
- Implemented a Vortex Database, loaded at startup
- Implemented Vortex/Sign-context-menu teleportation (scene change)
- Remove some of the useless folders to leave mostly the code