Added "Advanced Settings" check box.

Created new ScreenTools exported control for QML code to obtain screen DPI factor to be used for computing font point sizes. This code used to be in the tool bar code and now is available to all QML widgets.
Moved global mouse position tool into ScreenTools as I felt it would be a place to collect these sort of functionality.
Replaced Tree used in the Safety Component from a PNG file to a SVG file as the PNG was not scaling up properly.

Controls respect QGCPalette settings. Also added test window.

Starting point for real implementation

Summary page is also the launching spot for the setup screens. No more
left hand set of buttons.

Allows parameter access from QML among other things

Handy for testing without a real board

corrented file name

Instantiate a PX4 config view in PX4 mode from start, since boards with just the bootloader (or no working telemetry) cannot be flashed else.