Changed all fonts to pixel sizes

src/VehicleSetup/FirmwareUpgrade.qml

src/VehicleSetup/SetupView.qml

src/VehicleSetup/VehicleSummary.qml

src/ui/MainWindow.cc

src/ui/MainWindow.h

src/ui/flightdisplay/FlightDisplay.cc

src/ui/flightdisplay/FlightDisplay.qml

src/ui/mapdisplay/QGCMapDisplay.cc

src/ui/qmlcommon/QGCCompassInstrument.qml

src/ui/qmlcommon/QGCPitchWidget.qml

src/ui/qmlcommon/QGCSlider.qml

src/ui/qmlcommon/QGCWaypoint.qml

src/ui/toolbar/MainToolBar.cc

src/ui/toolbar/MainToolBar.h

src/ui/toolbar/MainToolBar.qml

src/ui/uas/UASQuickView.cc

src/ui/uas/UASQuickViewTextItem.cc