some updates

solution divided into projects, added basic state manager and basic
engine (implemented basic model of tractor's movement)
tractor stop feature + some minor engine refactor
added tractor class + velocity based movement
proper rectangle direction when going vertical
Logic + first-graphics (not implemented yet)
Trash deleted
.
Merge remote-tracking branch 'origin/master' into logic+first-graphics
fix issues
field development, field factory added, debugview

sowing feature only at the moment
delete old stuff