changelog for v1.31:
Added updated terrain + shaders for Salvador & Londrina;
Fixed AI trying to drive through pit building in first few pit boxes when exiting at Johannesburg Historic;
Added Diffuse Alpha Spec Normal Map Shadow Map shader;
Adjusted MR18 aero yaw sensitivity & engine torque in the low range;
Adjusted longitudinal load sensitivity of front tyres in several cars (helps preventing excessive locking up of the inside wheel);
Fixed an error in Marcas differential settings & added option for refuelling
Recallibrated AI performance in F-Reiza & F-Extreme to the latest aero revisions