If we get a dup, clear the default value since we can’t trust it

Also updated parser for new xml format

Use default font wherever possible. Where that doesn’t work, use
ScreenTools::dpiAdjustPointSize.

More consistent with Qml usage pattern

Also changed to pull specific small parameters set after cal instead of
full refresh. This way, the red/green indicators update much more
quickly.

If it doesn’t exist it will be prefilled with all registered categories
set to false

Moved update canvas signal to perspective load instead of hooking it to the paint event.
Added an "S" as the unit for the number of cells fact (as in 4S).