UI fixes, hair fixes, merges new hair

This fixes the toxin UI indicator (which Sayu accidentally did not
merge) and also gives red outlines to the low oxygen and dangerous
pressure indicators. Also, it slightly darkens the glowing outline
around the 'overheating' indicator, making it easier to see.

I have taken the liberty of fixing some oddities in the hair. The ones I
can recall off the top of my head are 'curls', 'dreadlocks', 'bedhead
3', 'bun',  and maybe some others? Can't remember, will have to go back
to fix more.

I've also manually merged the new hair from this pull request:
https://github.com/tgstation/-tg-station/pull/3178

I've already fixed a few things in the new hairstyles.