Early access: TurboFix 2.6.0

A few new features to properly support my upcoming handling pack, and some QoL work.

Changes for handling pack:

• Add a configurable turbo boost curve for different boost buildup behavior. Better represents whether boost comes in early and stays stable, or turbo lag and then all power at once.

• Support a monolithic base configuration as TurboFix/TurboFixBase.ini - basically support a master base list of turbo mappings. User configurations always have priority, this can be seen as an extra layer of info.

QoL changes:

• Change configuration management to Custom Gear Ratio style. Turbo configurations can now be edited and left unsaved. The menu can then be closed, while the modified-but-unsaved stay active, and once satisfied, these settings can be saved.

Upcoming handling pack?

(This section will be repeated for the next handful of mods to be updated, don't mind the copy-paste.)

I've been working on a handling pack! There was a lack of handling packs that worked nicely with a steering wheel. This upcoming handling overhaul addresses that, and utilizes the capabilities of my vehicle scripts (Custom Gear Ratios, Custom Torque Map, TurboFix and Manual Transmission) for the drivetrain, and applies tire and suspension changes through the full vehicle roster.