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

* 'master' of https://github.com/mavlink/qgroundcontrol: (21 commits)
  Hide wind rose until bugs are fixed
  Fix for centerChanged double signaling
  PX4 tuning UI: Remove unused params
  PX4 copy current custom modes
  Shorten the set mode retries to get feedback to the user faster
  New polygon center calc
  Delay creation of MAVLinkDecoder until it is needed
  PX4 Firmware plugin: First try to switch flight mode, then arm if successful - which is a lot safer than arming and then seeing if we can switch modes.
  Firmwareplugin: Trim retry period to something that matches closer the users attention and is still long enough to allow for multiple heartbeats to pass through
  Vehicle: Only expose deep-down protocol errors if actively enabled
  Fix trigger start for images everywhere
  Use trigger immediately for TRIGG_DIST
  Support for camera min trigger interval validation
  GoTo Location fixes
  index == -1: Show label in indicator and to the side
  Rectangle control which eats mouse events bleeding through below
  Bounding extension was too short
  Option to take images in turnarounds
  Update PX4 meta data
  Disconnect signals and force initial request complete if possible
  ...