Couple of C changes and a bunch of lua files to implement a gameplay-centric economy.

Simple changes to C code to support any commodity economy from lua.
Also, added the wayfarer economy lua files, and set it to start at
launch in event.xml. Wayfarer’s approach is described in
“events/wayfarer_economy.lua”

Ugens.lua and table2string.lua are utilitarian files and are needed for
Wayfarer to work.