Introduces framework (and icons for vox) for icon based species colors (because fuck the color wheel)

Created by: Intigracy

• imageadd: "Vox are now able to choose from 3 colors of skin (the current green has been darkened, a reddish-brown, and gray) in their preferences. Gray is the obvious best choice."
• tweak: "Vox raiders and adminspawned vox now get a random skin color. Admins are able to varedit vox skin colors by changing s_tone and regenerating icons."

I changed the default Vox sprite.

Species now have a mob reference to the human they're attached to. I needed to do this to make color changing work right.

The skin tone button on character preferences will now output the actual number of your s_tone for nonhumans.

Facial hair recoloring is now restricted to the same species as hair recoloring is.

Makes use of datum/species/handle_post_spawn to change the mob's color after species (and further, icobase) is applied already.

handle_post_spawn and regenerate_icons call updatespeciescolor(). I wonder what that proc does?

Vox icons are now in their own folder in the human_races folder, since there's more than 1.

Updates 2 unused procs in HELPERS in case anyone ever decides to use them.

proc/random_skin_tone() now has a species argument. It needs to use species.name if species is a datum, otherwise just use species.

Fixes vox not correctly creating vox footprints when running over blood.

Stops this from happening:

Tested as thoroughly as I can. 19 files change woooooo.