Gryffi 0.9.3

• The install script offers the document parser without the 30 GB disk
  check when its image is already on the server, for example after a
  reinstall.
• Quizzes in the player, and adding quiz questions and poll options in the
  builder, work over plain HTTP too (a test install with --listen).
• Opening a magic link, or coming back to a public journey with "Remember
  me", gives the browser session a new ID. A maker who is logged in in the
  same browser stays logged in.
• No more pg warning about overlapping queries on one database connection.