Bring back multiple debug levels

[BlueTemplar]

TL;DR

Multiple debug levels allow for situation-specific GUI tailoring.

What ?

0.16 had multiple debug levels (also accessible via F5,F6... keyboard shortcuts).
Please bring them (and more?) back - I believe F6-F8 are unused ?

Why ?

I was very nice to be able to switch with a single button press between :
- "no debug" (show-fps only),
to :
- "basic debug" (+show-tile-grid), for better planning,
to :
- "advanced debug" (+show-collision-rectangles and +show-raw-tile-transitions), when dealing with cliffs/ore/water...

I miss that in 0.17...

Other "modes" could be configured for situations when you have to deal with trains or with pollution...

[eradicator]

Oh. Yes. OHYES!

Preferably completely independant of each other instead of the current system where higher levels are forced to have everything from lower levels. That way it would be possible to have completely different overlays for different situations.

I.e. F5 Transport-lane debugging, F6 Train debugging, F7 Combat debugging, etc..

(Or just give us API access via game_view_settings or similar so we can do it outselfs.)