[Rewritten] Slime Person Colors
Completely redid this code per suggestions of Gia and Carn
No more blending icon operations, all possible slime icons are laid out in slimemutant.dmi
No more reliance on r_hair/b_hair/g_hair, slime_color has been added to track this in its place
---still relevent orignal notes---
This should help prevent xenobio from turning into a monotonous parade of blue identical looking slimefolk late round.
Taste the completely cosmetic rainbow!
http://i.imgur.com/WaK4EKn.png
Merge pull request #1 from tgstation/master

test
Merge branch 'master' of https://github.com/Incoming5643/-tg-station
Merge branch 'master' of https://github.com/Incoming5643/-tg-station

Conflicts:
	code/modules/mob/living/carbon/human/update_icons.dm