Outdated Gavril D15 2001 Restyle 1.3

A small update to fix compatibility problems with 0.8 & 0.9

• Replaced snorkel/supercharger package with official snorkel and a supercharger.
• Redid some slots to make part swapping a bit easier.
• Updated roamer_shared to current roamer jbeams
• Changed custom variant to use body-coloured trim
• Updated radiators to their proper normal/heavy/race variants

There will probably still be some issues (diffs being wrong, etc), but this is just a temporary update to get this up and running while I work on a much bigger update. Cheers!