Remove ArduPilot Follow Me support from Stable

timer.start() and timer.stop() were breaking the 'running' binding of
the timer

Change follow to work above home altitude only

Support both relative and absolute FOLL_ALT_TYPE

This adds support for the new ArduSub 3.0 feature of automatically detecting
the thrusters directions and reverting the corresponding motor output if
necessary

Fix Follow X/Y calc from distance/angle

Use consistent "Launch" naming

Disable closing app on last window close. This will close
the app on every widget spawned in QML that closes (MessageBox)

Reword to use sizeToContents on combos for flight mode channels

Except for motorIndexToLetter()

Fix textRole usage for QGCComboBox

Update for missing params on rover

Follow page not showing up for Rover

Change jscript usage to make Qml compiler happy

Better handling of unsupported class/frame combinations

Update for 4.0 releases