RMI Silverstone 1975 THR new AI 0.2

Previous version featured edited AI spline from the track, this update brings a complete rewrite of both AI spline and AI hints, thanks to the Parrila method.

Intended for the THR layout but it should work on the original one too.
(Tested with rss70/f1 classic 1975/drm/acl gtr/acl gtc/berta tornado/rd1 porknose/mckeown 911)

Back-up rmi_silverstone_1975\THR\ai\fast_lane.ai before install


Thanks RMI/THR