[Indoor] Balcony building parts

[Tobias Knerr]

Hi all,

I'm involved in a discussion about handling balconies for 3D rendering:
https://github.com/tordanik/OSM2World/issues/241

We've previously touched on handling balconies in the context of 
(quasi-)indoor mapping. I would appreciate your thoughts on this 
proposed building part value, and especially the questions relating to 
SIT. This would help refine my own thinking and my decision on whether 
to add support for this tag to my 3D renderer.

Yours,
Tobias