Merge branch 'master' of https://github.com/mavlink/qgroundcontrol into offlineMaps

* 'master' of https://github.com/mavlink/qgroundcontrol: (120 commits)
  More fixes for line sorting
  InstrumentSwipeView: update current page index on page change
  Bugfix for vehicle health instrument view
  Better error reporting for unknown command
  Optional camera mode support
  Update README.md
  Guided fixes
  Fix typo
  Solve problem with windRosePie Focus
  Add armed indicator for Sub
  Add USB json config for CF2
  Some simple fixes
  Correctly place firmware plugin instance data with Vehicle
  Survey area is always convex polygon
  Solve some typos
  Remove lost code and update z position of pie
  Change pie color with theme
  Change wind compass color with theme
  Make wind compass to be only visible in fixed-wing
  Add support for SET_CAMERA_MODE command
  ...