Changes to Bulldozer mode:
- requires a FARL at both ends of the train (direction doesn't matter)
- removes stuff in front and behind the train
- doesn't place anything besides the rail it drives on (and removes it afterwards)
- readded Maintenance mode: removes old layout in front of the train and places the new one. You still have to steer it yourself
- removed -root mode, nearly the same results with bulldozer now.
- select a land tile nearby when replacing concrete (less odd looking stripes of land)
- fix concrete being removed when activating bulldozer
- fix error when picking up stone path
- removed unused/old settings
- minor performance improvement (?)