Getting settings out of data structure so that they're not trying to be undone.
Normalize default segments, too.
Clear undo stack when switching units.
Further work on the street width selector.
Fix rounding errors that would make segments stick weirdly to edges.
Fix remaining width rounding errors.
Fix rounding errors.
Style changes for the width input box.
Fix for the width chart.
Fix red colour in the width input box.