Fix crash on exit due to bad parenting/shutdown sequence

Flyview overlay

* 'master' of https://github.com/mavlink/qgroundcontrol:
  Pile of bug fixes
  Permit firmware to send responses until stdout handle is drained
  Add mavlink console support
  Deprecation comments
  Fix plan view geofence display
  Fix mock link calls
  Mavlink submodule update

Added top/bottom alignment state to map scale
Allow disabling instrument widget altogether
Added an otherwise redundant row to PlanToolbar so it matches the same button position as the main toolbar
Fixed typo (Math.max()) in ScreenTools
Fixed Javascript Exception in OfflineMap
Increased the import window size in OfflineMap
Added function to MainWindow to disable toolbar for a truly modal dialog
Added code so clicking on an open toolbar indicator will cause it to close

Add mavlink console support

Bulk mission altitude change, plus pile of bug fixes

UAS: Deprecation comments

Mavlink submodule update

Fix plan view geofence display

Yet another guided bar rewrite

Plan toolbar: Layout fixes to keep things from moving around

Plan: Support battery calculations

Pile of bugs fixes around map positioning

Plus low battery announce changes

Major cleanup to Guided Bar: visuals, states, bugs

Survey: Hover and Capture support

Plan: Support for images in turnaround on/off

Fix gimbal visuals

Fix follow vehicle recenter logic

Add resume mission support

Allow custom plugin to provide its own position source.