[WIP] Static batteries

https://github.com/CleverRaven/Cataclysm-DDA/issues/2514

Static batteries part 1. Still needs work on crafting, spawning, balance, and removal of the old batteries.

Works by swapping same-size batteries (by max charge), but currently no way to remove batteries from a tool without a spare.

Code for a rechargeable tag in place, but currently no way to add that tag to a battery. Still needs testing whether recharge-tagged batteries stack with each other, or if they merge with non-tagged batteries.

My current thoughts are that batteries won't be able to be crafted (and if they are, have less max cap ala makeshift), but will be able to be combined to make larger batteries to fit in extended tools. Possibly make extended battery tools not-quite-double? Also, with this change, batteries might need to either last longer or have more initial charge. I'd also suggest creating the ability to spawn tools with variable charge, you know, like a radio someone used a few times before you found it.

Needs a lot of work.