Added several variations of the Chevrolet Low Cab

note: this truck is referred to as "chevy_low_cab" in the game files, however it originally had an ISUSU logo on it
I've decided to keep the old ISUSU branding as an optional bodygroup, but the truck now has a chevy logo as I based it on the game file name

fixed missing wheel textures whoops

Added several variations of the Ford Crown Victoria
Added Hyundai Santa Fe

Added Lincoln MKT
Added Lincoln Navigator
Added Lincoln Town Car Limousine

Tweaked some modern lights, namely the 2015 mustangs, the tesla model S and the range rover

Added Cadillac ATS
Added Chevrolet City Express
Added several versions of the Ford F-350

Tweaked Audi A6 handling (brakepower from 35 to 55)

Initial addon creation.