Fixes SmallJoker/bitchange#9

This limits the tools a shop will accept or give to those whose wear is less
than or equal to the tool shown in the Owner needs or Owner gives lists. This
protects both owners and customers from unfair trades. Owners are protected
from receiving worn out tools when a new tool is placed in the needs list.
Customers are protected from receiving worn out tools when a new one is placed
in the give list.

substitute deprecated tile_images and height_min/max with the new ones

Clean up the position entry on leave
Add wrench support

To stop crashing with nil instead of pos.

- Rename bitchange_ -> bitchange.
- Better coding style
- Run OptiPNG

Added tool repair node to .. repair tools with money