The flow layouts footnotes twice in some cases, which messed up the Vt's locator state. Typically, we use `thing.measure` instead of `thing.layout` to prevent side effects, but in this case it was simpler to just undo the modification. A future layout engine rewrite should try to make this kind of error harder to make.
Fixes#1597
This positions placed elements relative to the real container size instead of relative to the base size of the region. This makes its usage more versatile.
Fixes#82Fixes#685Fixes#1705
Laurenz