Hopper 0.5.0

• Hopper says when a newer release is out: "V update to …" at the bottom right. V says
  what's in it, V again installs it, and then reopening Hopper puts it in use. Conversations
  keep running meanwhile.
• hopper update installs the latest release from a shell.
• "check updates" in settings turns the check off. A copy built from source never checks.