New tab type

[Monroe1701]

I like to propose a new form for the tab to allow for a dual label system.
It is hard to explain, it is basically two tabs in one, one at 45 degrees on the inside and one 45 degrees. that way you can read the label even if the boxed are on a shelf or stacked. (both need to be 45 degree for the outside to be better readable from higher up)

Please see https://luckyresistor.me/3d-printing/storage-boxes-system-for-3d-print/ for images.
I think this dual label system is genius, but I like your boxed better, because of the flat bottom and the possible scoop.

I tried to implement it myself, but I have to admit I couldn't event find the position in the code to do so.
It would clash with #73 "Tab without support", but would give that "wasted space" a good reason to exist.