• Added a selectable list of GeoPackage layers to the "advanced options" import menu in the web UI.
• Added a layers= to the -i command to allow importing a subset of GeoPackage layers.
• Improved GeoPackage i/o. Topologically related layers are imported together, so -simplify and other commands can edit them together. Unrelated layers are imported separately (with a different arc table), which allows -simplify to be applied more selectively.