Add option to sort power grid loads and charge %

[paneras]

Just what it says in the title. In some maps, the amount of areas that the power grid shows is a lot, and it would be nice to have a way to sort all of these APCs, especially Loads and Cell Charge. That way we can have a quick glance and see which areas need to be powered incase of an arcfiend, pipebomb or any other emergency.