PX4 multi-battery setup

Remove unused code

- add NOTIFY for distanceSensor property
- add DistanceSensorReadingsChange() callback prototype

- revert excessive NOTIFY
- adding MaxSensor into DistanceSensor frame handling

- add proximity radar view in map view
- add proximity radar view in video view

change distance label positioning in video view

clean up unwanted comments

- space up proximity sectors
- revert unwanted changes in qgroundcontrol.qrc

squashed commits

Less twitchy value grid width sizing

Unified photo/video control which works with mavlink cameras and just video stream

Remove unused code

Telemetry Values bar at center bottom

Ready To Fly support based on MAV_SYS_STATUS_PREARM_CHECK

New Transect common controls

Tweaks to toolbar visibility

Modified support for multiple first run pages. Added first run for offline vehicle settings.

Added configurable value grid to toolbar

ToolStrip rearchitecture for encapsulation and customization

Re-architect toolbar for better customization capabilities. Also use less real estate.

Rework Fly View into separate layers which can be customized at each layer.

More FlyView encasulation. Make QGCPipOverlay completely self contained

More work on encapsulation in Fly View

Fly View: Move business logic inside controls

Major rework to support terrain profile display and terrain collision reporting

Support for reusable InstrumentValueArea control

Refactor instrument value controls

Set RC To Param support

QGCPopupDialog support

Mavlink terrain protocol support

Integrate Create Plan overlay in File DropPanel

New Create Plan support

Corridor edit toolbar

New reusable file dialog for KML/SHP loading

Save/load main window state

Rework presets

Use TabBar in Complex Item UI

New QGCOptionsComboBox control

Allow split of current segment

FW Landing slope heights display

New QGCDynamicObjectManager support

New MapLineArrow control

New base class control for Survey/Corridor