Change disconnect model for vehicles

Fix virtual joystick polling rate

small fix to recognize clone px4flow units

This guarantees we are past bootloader on all OS. Window tends to not
detect bootloader, connect to it and then get confused.

Windows OS doesn’t disconnect port when you pull plug on USB. This
caused all sorts of problems with previous logic. New logic handles
this correctly.

Thumb stick

First pass at Comm Link settings (in QML)

* MavLink/master:
  Fix MultiTouch

Conflicts:
	src/QmlControls/JoystickThumbPad.qml

Fix virtual joystick MultiTouch

Virtual thumb joystick

Fixing black on black font issue.

Added extended GPS Info

* MavLink/master:
  Fix UDP Auto-Connect for iOS.

And other toolbar fixes...

Fix UDP Auto-Connect for iOS.

Telemetry RSSI

Added toolbar indicators popup (drop down) showing extended information.

Send mission item vehicle trashing float values

Fix telemetry radio RSSI calculation for SI1000 based modems

New item uses altitude from last item