TheDarklingWolf/Cataclysm-DDA — pull request #488 by ethankaminski (2013-04-14 01:54:11+00:00)
Title: Add "extra battery mod" item, and make recipes book-learnable

Added an "extra battery mod" item that doubles the battery capacity of tools. The expected way to get this item is to learn the recipe from "What is a Transistor?" or "Advanced Electronics", and then craft it.

Also made recipes capable of being learned from books, in order to support this item.