update v17.6

-   

    - Prepatory additions to build the foundations for future themes such as the shopping mall -
-

- Added a thickness half tile for each floor type (40+)
- Expanded the glass railing and added 2 new railings 
- Added a suitable wooden staircase and a new column
All this stuff can be found in the related new theme file "17_Visible_Upstairs_System"
-
Here's a usage example!

*Everyone who already bought the asset can get the new stuff for free

See you and happy game-making! :)