Version 0.18 released

Today I released V0.18. Now the adult version is also available for the first time for 1.99 USD. The censored version remains available for free.

Change log:
- added iron ore and iron
- added rocket engines

Fixed bugs:
- player was moved away from the driver seat during crashes
- game chrashed, if a player drove to far with a vehicle
- moveables disappeared for client players in some cases

- rabbit holes spawned to many rabbits at the same place
- problems with changing clothes while being in a driver seat
- player wasn't able to move after being in the inventory on a moveable
- issue for hosting player, when a player quit the game without pressing the "disconnect"-button

Changed:
- the source code, when a player sits down in a driver seat