Physics update for 1937 GP cars 1.5

Fuel tank position fixed. a heavy fuel load doesn't disturb the balance of the car too much. original values make a heavy
car oversteer.
ERA handling fixed, default setup of Auto Union improved.

Due to improvement in cars' handling, tyre grip has been reduced slightly to keep lap time realistic

I hope this is the final physics update. future updates will focus on track support. Due to AC's bug, 1937 car's high top speed and weak brakes, Ai can't look far enough to brake properly after a long straight. special AI splines are needed for Barthurst 67, Gnoo Blas and Long Ford. and of course Pescara when that track is released

Center of Gravity of Auto Union moved to the back of the car. original value of SimDream puts it at the front, which is wrong.
With this modification, the Auto Union now has an oversteer feeling. and everything else, including engine power, suspension, AI even graphics, has to be adjusted because of this change
Other fixes include increased rod length for maserati and era, so that they don't ride on packers

Sorry for posting "big physical update" even at version 1.4

Corrected fuel usage for all cars, fuel consumption estimation now matches actually fuel usage at monza
Alfa Romeo and Era have better acceleration at low revs.
Slight adjustment for default brake bias.
added Ai support (creates separate "layout") for Gilles 75(?)'s Reims and Sergio Loro's hockenheim 67 GP track, so that ai cars don't miss the braking point and crash at the end of long straight.

1. Updated AI behavior for cars (AI.ini), they no longer cut the inside the corners and can run on macau and pau 1967 in an acceptable manner. Autounion up shifts better
2. Mercedes turns less to the right when under throttle. the effect is now only slightly noticeable, and is no longer an annoyance.
3. Autounion less likely to have broken suspensions.
4. Maserati and Era use less fuel
5. updated track ai configs

Added Le man 67 ai update for 37 cars, otherwise they'll miss the braking point of mulsanne and crash. (it seems to be an AC bug as it also affects Legion's Alfa Romeo) the trick is when recording AI spline, swerve the car before mulsanne (at the 150 marker) to create an artificial chicane for AI

reduced the front ride height of mercedes and alfa romeo

other minor bug fixes

Nurburgring nordschleife "37 layout" is no longer required

you can safe delete the following files/folders

C:\Program Files(x86)\Steam\SteamApps\common\assettocorsa\content\tracks\nurburgring1967\models_nordschleife37.ini (file)
...\assettocorsa\content\tracks\nurburgring1967\nordschleife37 (folder)
...\assettocorsa\content\tracks\nurburgring1967\ui\nordschleife37 (folder)

Finally got all problems fixed.
I had a few races with them and can stay on the track without crashing for at least half an hour.
These are the most stable/drivable 1937 cars. still Mercedes, Autounion and Alfa Romeo are more difficult to control than F1 1967 cars

slightly reduced the power of alfa romeo, and adjusted the suspension settings of mercedes