config overrides for vanilla objects use += operator

mostly just updated to work again.
the oven currently does not appear to have a temperature when you look at the inventory screen but it actually provides some heat to players in a small radius when in use.
animations and emissive materials now indicate which cooking slots are in use (no more hotplates running with nothing on them). if you switch on the oven with no cooking equipment attached the only indication will be the interior light switching on. if you then attach cooking equipment the appropriate knob/indicator/element will be activated.