Changed Joystick._exponential from bool to float. It can now be set between 0 and -0.5 by user using a slider.

This makes VehicleComponents reusable from core plugin without
requiring override of prerequisiteSetup

No more user prompting

Shows touch area extents when turned on

For showTouchAreas and showAdvancedUI

- Fix imports to support 5.7
- Move properties to correct location