-floorbuilding stones:
- st_wood (random orientation), st_wood_h, st_wood_v, st_wood_growing
- st_flhay
- st_flrock
modified features:
- keep identity from seed to stone, from stone to floor
- eliminate stone killing within on_move(), it is done on floor change only
- let stone fall on first occurence, even if multiple impulses are received
- rename some floors:
- fl_abyss
- fl_ice
- fl_water
- fl_swamp
- fl_space
- fix greek language menu