Remove cold slowdown entirely

[Nnystyxx]

I have no objection to bare space exposure being very, very, very bad for you. I'm moreso disgusted by 'oops! it's cold somewhere in this hallway, you are now slowed to a crawl instantly. also this will be this way all round'.

Flab's idea is also rather nice and I understand the perspective that basically these systems interplay awfully rather than coldslow being totally an issue. It all just happens too goddamn fast and is too goddamn hard to fix.