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

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.

Controls respect QGCPalette settings. Also added test window.