v1.2

Fixed

• Rotating the phone no longer loses your place. The viewer
  re-derived its position from the row it read when the map was
  opened, so turning the phone didn't re-fit where you were looking —
  it threw you back to wherever you started.
• Maps now reliably reopen where you left them. The position was
  written as the viewer was torn down, on a scope that was usually
  already cancelled by then, so going back — the normal way to leave a
  map — frequently dropped it. Backgrounding the app lost it outright,
  since Android kills processes without warning the screen.
• The back arrow was under the status bar, and being a bare icon
  drawn on the map, it vanished over dark areas. It now clears the
  status bar and sits on a translucent disc.

Changed

• Text and thin lines are sharper at most zoom levels. Tiles are
  rendered finer than they're drawn and then scaled down — by nearly
  half, just past every doubling of zoom. They were being filtered in
  a way that undersamples exactly there, which made hairlines shimmer
  and thin routes drop out.
• Less of a smear while sharp tiles are still rendering. The only
  fallback underneath was the whole page at fit scale, magnified up to
  24x. Where a closer level is still cached from zooming in, that now
  gets drawn instead.
• Library rows are readable. Thumbnails were rendered at 256px and
  then squeezed into a 48dp square, so a wide map used about a fifth
  of it. The box now matches the shape of a map.
• Rename, favourite and delete are no longer hidden. They were
  long-press only, with nothing to suggest they existed. Rows now have
  an overflow button, and the actions open in a bottom sheet instead
  of a dialog.

Installs over v1.1.1 without uninstalling.