I'm going to restructure the assets

The set of assets has grown a bit, and by now I think I can reasonably well structure them into categories. I will do so and replace the existing download files with new ones. The assets will stay the same, they will just go into different sets a la:

• Housing
• Fortified structures
• Roads
• Misc village elements
• Nature

Maybe there are more categories, but these will make the assets more accessible and better graspable.