Real skins for Pessio's Mustard Bull 0.1

This isn't much - just a quick and dirty sponsor swap on the skins that come bundled with Pessio's excellent Mustang 302 Mustard Bull Trans-Am racer.

I've also added some authentic details to a couple of the skins, and created a set of Firestone Golden Rings for Parnelli Jones' #15 car. Finally, I've added two extra factory colors: Grabber Blue and Calypso Coral.

In total you get 12 skins - 4 factory colors, and 8 racing liveries.

N.B. The skins don't replace the originals.