Vehicle collision tweaks

Fixes #9005 
Terrain and furniture now has a set of flags ("NOCOLLIDE", "TINY" and "SHORT") that limit the ability of vehicles to collide with the flagged terrain.
NOCOLLIDE does what it says.
TINY only collides with vehicle wheels. (mostly flowers, as per #9005 )
SHORT does not collide with vehicle parts labelled "PROTUBERANCE", which is mirrors, blades, and external fuel tanks.

More WIP is running over items, right now a vehicle running over an item does rng(1, 5) damage to it, if the total damage reaches 5 the item is destroyed.  That may or may not be ok, if that's too limited to be included and a simple alternative isn't found, I'd rather pull it than sink a lot of time into it right now.