update v17.8

"Discord Suggestions" is a short series that will feature random prompts
from the #suggestions channel on our Discord Server.

The aim of this serie is to chop down the long suggestion list, without
having to wait a specific theme. 

Each batch will last 5-10 updates and is planned on a bi-monthly basis (~)

-

- Added a modular net tileset to border the junkyard zone (and any other)
- Added a couple of new danger signs + hanging version
- Added a couple of barrel variations with a green liquid inside
- Added a car wreck (2 versions)
- Updated the theme files with the new stuff

See you and happy game-making! :)