Stable merge

PX4: Warn if HITL is enabled on vehicle

Move position of HITL to bottom. Handle no SYS_HITL param.

Warn if SYS_HITL is set

Fix debug output

Use correct number of available channels

Appveyor: Switch to Stable 3.5

USe correct number of available channels

Bring fixes from Stable_V3.5 -> master

Use any libicu version

Fix typo in CodingStyle.qml

Structure Scan: Add support for Start From Top/Bottom, plus more helpful stats

Add support for Start From Top/Bottom, plus more helpful stats

PR android joystick improvement v2

When starting up, if you start the GS before connecting the bluetooth joystick the QGC needs to be closed and restarted to get it to recognize the joystick

Fix crash bug that could occur when reconnecting a camera.

Make Apple happy

PR Taisync support for Android

Fix typo of not to note.

Link to any found version of libicu.

Switch to Stable 3.5

OfflineMaps: Fix tile set counts

Fix tile set counts in offline maps

Store correct tile set counts for image and elevation sets.