Allowed you to pick up and spend metal.

This is pretty hacky right now.
"dig" an all-metal tile to pick it up.
Each object costs an undocumented, code-duplicated
   amount of metal.
Fixed robot volume stuff

Visually indicated the max stuff you can carry,
   as well as the current amount of stuff
Increased robots' volumes so they can carry more stuff
Reduced autorobots' capacity so they don't carry more
   than their volume; also their cost + volume carried
   totals to less than their volume