Fixed cell chargers being infinite energy sources
Updated PACMAN comments.
Fixed air alarm heaters using 1000x less power...

...than they should. Note that MAX_ENERGY_CHANGE is 1000, so air alarm
heaters will now draw a maximum of 1 kW instead of 1 W, much more
befitting of a heater.
Merge pull request #4922 from mwerezak/power

Fixed cell chargers being infinite energy sources.