Changes

Model should have its origin point set accordingly as the model will be placed directly on it's its corresponding locator. Axle model must contain at least one pair of wheel locators and if the axle model uses its own shadow texture, then it must have its own shadow texture caster locators (defined same as the chassis ones). Additionally, axle models can have several wheel pairs attached to it, but all of them must have the same ''steerable_axle'' value. Axle models can also contain locators for hookups (e.g. lights) and accessories (e.g. bumpers).