v0.8.0

Changed

• The daemon reads the live gimbal pose (0x0043) every second only while a client wants it.
  A watch connection asks with the request ["live-pose", "on"] (and "off"); the poll runs
  while at least one connection has it on, a closed connection counts as off, and a new one
  starts off. Without a subscriber pose in the state events changes only with the full read
  every 5 s, so fewer queries hold the camera lock. New capability live_pose_on_demand; clients
  that never ask no longer get a pose every second (#68).