Drivetrain interface improvement & and debug console interface.

[Eagle]

Hi!

I was tinkering with the systems lately, and i noticed the drivetrain interface couldn't support more than 6 gears (haven't tried to test with less though). It's quite uncomfortable for modding and making presets.

The second point is very unlikely to happen. It would be a console that shows certain loaded files and displaying configuration errors. MaxSCL already has something similar when loading/parsing a bike, so, i don't think it would be a pain to build.