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.

Tool bar buttons now use QGCButton as base to inherit hover mode fix.
Made QGCButton.showHightLight into a public property so I could use it as a trigger for repainting the chevron button.

Also realized I don’t need __lastMouseXY

Reduced size of the main tool bar buttons accordingly.
Connect/Disconnect buttons (and link configuration combobox) now use the default height.

Passing parameters QVariantMap across C++ boundary was causing crashes
in Qt due to Qml array bugs. Referencing same Fact* across Qml boundary
in multiple QQuickWidgets caused jScript GC to crash.

Switch QGC firmware upgrader for PX4 to AWS and Travis. Use beta/stable/master for Firmware, map all three items to master for Flow (because there are not beta/stable branches)

Button too small for when it switches to disconnect (multiple links adds a drop down icon to the button).

Will rewrite singleton shutdown in separate pull

Also turn them back on

Although this should theoretically be a no-op it causes a crash in
Windows when running unit tests. Also parent toolbar in constructor.

These tests that make direct calls into the tool bar need to be updated.

Correct order of rotations to get roll, pitch and yaw corresponding to classical aeronautics convention and coherent with Fly view