[MC-45213] New skins: Outer layer not showing / body parts showing black.

Moderator Note

The skin system has changed for 1.8 including new layers, new skin templates are required.

Use as template.
See http://minecraft.gamepedia.com/Skin#Creating_a_skin

I'm not sure of the pattern here, but whenever I have a jacket texture and no sleeve textures, my left arm turns completely black. Will continue updating in the comments as I break it more.

Note that it appears that my (classic) arm texture is turning black, not my (new) sleeve.