Small Update V 0.5.0

Added some more AI car types to race against (to match players chosen car)
Added tyre friction variations to AI cars,
Tweaked the racing AI (ongoing)
Added more ambiance to some tracks,
Added pit lane messages, to warn of low fuel etc,
Added engine damage, car now gets progressively slower the more damage your car has upto a max value (approx -5 to -10MPH), repair it by going through pit lanes,
Added game tips to the loading screens,
Custom Tracks now temporarily locked,
Fixed some bugs.