ApolloShell 0.1.2 Patch 2

A patch on 0.1.2.1: a light theme on a dark Mac, and three ways to lose
work or run an action twice.

Fixed

• A light theme lights up the whole shell, and a dark one darkens it.
  Around a hundred places take their text colour from macOS, so a light
  theme on a dark Mac wrote white on its own light surfaces. The token
  --apollo-theme-appearance: light or dark now sets the appearance of
  the app itself; auto follows the system as before.
• A click on the screenshot, lock or colour picker button runs once.
  The control centre stays clickable while it fades out, so a double
  click ran the action at once, with the glass still on screen, and a
  second time after the fade.
• An unreadable pinned.json is kept. Nexus read a broken file as an
  empty list and the next pin wrote that empty list over it, so a typo
  made while editing by hand cost every pinned app. The file is copied to
  pinned.json.unreadable first, as settings.json and usage.json
  already were.
• "Restart now" stays while an update waits. Checking again picked the
  downloaded update up a second time, and Nexus > Updates showed it as
  found instead of ready, without the button.