[1.04] Rare wallwalker bug

[grmblfzzz]

This has been around since various 1.0 changes at least, not sure if it's been reported but here goes anyway:

Rare wallwalkers (banshees/dreads/xorns/umberhulks/etc) don't seem to have the base version monster type ability to see through said walls. Notice it a lot since I'm such a track fan. As a rule, they just hang out there where 90% of the people would never know they exist. Have to tunnel up to their faces if you want to fight them.

[cttw]

This can also happen when wallwalking enemies get knocked back into the wall. Sometimes they dont see you and dont come back out and you have to dig for them.

[grmblfzzz]

It's also a LOT more common than I bet most people realize. My first order of business is to get track on any of my dudes, and on my TW here just going through sandworm I've already come across 3 rares just perma-oblivious until you dig to them. The rate goes up as the game progresses, as banshees/dreads are introduced.

Further, I think there's some more subtle issues with rares not getting all the stuff the base creature type has. Rare snakes don't have the sweet/frustrating snaky movement, for instance. Only really flagrant problem is the wallwalkers, but I suspect properly granting all base-type abilities would fix subtler/more obscure issues as well.