Was used for run-time efficiency, but it wasn't really ever set beyond one layer-height, which made it rather useless.
frontend part of CURA-11157 -- needed version upgrader as well, since it's the first alteration
A lot was changed in support. The short of it is that we now think towers should be on by default, but aren't _completely_ certain about it. It makes more sense to do make this change before the beta rather than just before stable, so we have a chance to revert should it prove disastrous.
