remove SITEBLOCK_BLOCK from tiles with SPECIAL_STAIRS_DOWN

[jaksd]

For issue #1

[Kamal-Sadek]

Thanks for the commit! We might want to go back and add other objects (STAIRS_UP) to the check. I'll also go back later and check the csv file, because the issue likely came from there.

[jaksd]

Thanks to you too!

might want to go back and add other objects (STAIRS_UP) to the check

That's a good idea, I'll have a look at that. I'll see if I can come up with something more elegant too, at the moment I'm thinking we should remove any doors adjacent to a stairwell with this issue as well since a door that you can walk around due to empty space around it doesn't make much sense. And ideally we should be checking that there is actually empty traversible space next to the stairs (so we aren't trapped inside a 3x3 block of wall)

check the csv file, because the issue likely came from there

I tried to figure this out but I couldn't find a csv file for the prison, could it be using the old map generation code?

[Kamal-Sadek]

Indeed, it doesn't have a csv because it's being loaded from sitemaps.txt in the art/ directory, under GOVERNMENT_PRISON. This might be a slightly bigger rabbit-hole than what I was expecting.