Adds json-moddable tool groups

(Suggestion thread: http://smf.cataclysmdda.com/index.php?topic=3501.0)
This first PR adds a system to read in an arbitrary number of tool groups, which can be substituted for normal tools in recipe entries. On the crafting menu you can switch between viewing the condensed tool list with groups displayed, and viewing the full list of tools.

No tool groups have been added yet.