Notes regarding unmapped f_info.txt features:
- 'DARK SPACE' doesn't need to get mapped, or rather, is already mapped, as it's just an empty rectangle.
- 'ARCADE' mean these features are only for the dedicated ARCADE_SERVER.


65-73	road

(74	shop	--probably requires some coding as shop symbols aren't mapped directly from f_info.txt but via CS_SHOP)

(79	perma-clear wall	DARK SPACE)
(108	bottomless abyss	DARK SPACE)
(121	empty sky		DARK SPACE)

181	field

(228	ai tron (ARCADE)	--looks like a player ie '@' so not to map at this time as we don't have player-specific mappings yet.)
